Product range

VibraSens designs and manufactures products in the field of dynamic instrumentations.

Our core expertise lays in the:

• Industrial piezoelectric accelerometer design and manufacture
• Piezoelectric pressure sensor design and manufacture
• Signal conditioning for piezoelectric vibration sensors and vibration transmitters : charge converter, constant current source, .. .
• Cable assemblies using coaxial or twisted pair low noise cable.
• Junction box with BNC or switch interface unit.
• Accessories such as mounting stud, blocks and magnetic adapters.
• Calibration services for piezoelectric accelerometer, dynamic pressure sensor and vibration signal conditioner.

Mission

Vibrasens' mission is:

• Be one of the European leaders in the manufacture and design of piezoelectric accelerometer and piezoelectric dynamic pressure sensor.
• Offer innovative piezoelectric vibration sensor for niche market and harsh environment (700°C).
• Offer private labelling of our products for companies who want to outsource their piezoelectric accelerometer and pressure sensor manufacture.
• Be the ideal partner in terms of pricing, reliability and technical support.

Industry served

Our piezoelectric accelerometers are used throughout the following industry :

• Power generation (Gas turbine, Steam turbine, Wind turbine, Hydro generator)
• Petrochemical & Pipeline industry
• Offshore platform industry
• General process industry
• Research and development facilities
• Metals & Mining
• Pulp and paper
• Waste water treatment
• Research and development
• and many others.....

Applications

Industrial piezoelectric accelerometers can sense vibrations in terms of acceleration, velocity and displacement for machines such as :

• Air compressors
• Air handlers
• Pulp and paper dryer sections
• Conveyors
• Cooling towers
• Fans
• Fourdriniers
• Gear boxes
• Motors
• Press sections
• Presses
• Stamping
• Pumps
• Roll and process equipment
• Spindles, ..

Experience

We have more than 20 years of experience in the piezoelectric accelerometer design, especially in harsh and high temperature environment (500°C, 700°C or even more).

In order to maintain our international expertise we closely work with two university laboratories LCEP ( http://www.lcep.ens2m.fr ) and LPMO ( http://www.lpmo.edu ) based in Besançon and specialized in Piezoelectricity.

We also have the chance to be located in a region where piezoelectricity, microtechnics, microelectronic, mechatronic, microsensors and precision are well known words. Besançon hosts one of the biggest microtechnology fair in Europe ( http://www.micronora.com ) devoted to microtechnology and strong of 850 exhibitors from 25 countries.

All this friendly environment strengthens our knowledge and gives our company a competitive advantage in the piezoelectric vibration sensor technology.

Technology

With advanced product development and manufacturing facilities in Besançon-France, VibraSens has the skills, experience and resources to provide the products and services that will fulfill your requirements.

A modern production facility exclusively engaged in the design and manufacture of piezoelectric vibration transducers, piezoelectric pressure sensor and vibration instrumentations help us to maintain a high quality level in our core business.

Our manufacturing and test equipment ranges from basic precision machinery for providing high quality sensor components, to custom-built machinery specifically designed for piezoelectric vibration sensor fabrication.

During the years of development we have also built some specifically design systems to test our range of piezoelectric accelerometer. We have developed using ®Labview (National Instrument Trademark) a completely automated shaker test system to check the sensitivity and frequency response (up to 10 kHz) of our piezoelectric vibration sensors.

Our controlled process includes laser and microplasma welding, helium leak tester, resistance welding, temperature cycling, high temperature brazing. All those processes and others are strictly controlled by our process specification document.

We closely work with one of the best European company specialized in the manufacturing of hybrid circuit for the sensor industry. With this partnership, we are sure to stay ahead of this technology for the years to come.

Why should you buy from us:

We are focussed on the manufacture and design of piezoelectric vibration sensor. We could offer you the best quality price performance on the market.

We invest heavily in our core business and keep all of our products up to state of the art technology.

To better suit your market, we offer private labeling for all of our product line with two digits modifications in our part number.

Whatever your market is, condition monitoring, balancing, vibration diagnostic services company, we will be happy to serve you and share our extensive expertise. We are looking forward to being your vibration sensor partner.

 

VibraSens designs and manufactures piezoelectric accelerometer only. We can also manufacture using commercially available chip, capacitive or piezoresistive accelerometers.

PIEZOELECTRIC ACCELEROMETER SELECTION

Because they cover the broadest range of applications, piezoelectric accelerometers are among the most versatile.

Their main characteristics cover the range:

• temperature from cryogenic to +800 °C
• frequency from 0.1 Hz to 50 kHz
• resolution from 1 ug to 100 000 g

Their physical characteristics cover the range:

• Connector or integral cable
• MIL, industrial, RF connectors
• Few grammes to 200 grammes
• Stainless steel, aluminum or titanium material
• Hermetically or epoxy sealed

In a first approach, piezoelectric sensors can be distinguished by:

• Output (AC or DC, acceleration, velocity or displacement output)
• Piezoelectric material (ceramic, quartz, tourmaline,...)
• Transmission type, ®ICP, current, 4-20mA,....
• Stainless steel, aluminum or titanium material
• Hermetically or epoxy sealed

The table below sums up technology commercially available.

 

Piezo	Trans- mission	Out- put	Temp.	Pros	Cons	Application
PZT ceramic	®ICP (1)	Acc AC	-55 to 150°C	High reliability Higher resolution than quartz Versatility (2) High volume production Low cost Numerous option (5)	Less stable than quartz	General industrial vibration monitoring.
		Vel. AC	-55 to 120°C	No external signal conditioning	Low reliability Lower temperature Sensitivity, frequency range and full scale is fixed No evolution 3) Limited options (5)	General industrial vibration monitoring.
		Dis. AC
		Vel DC		No external signal conditioning and processing		Industrial vibration process measurement where signal (4-20mA, 0-10V) is connected directly to PLC
Quartz	®ICP (1)	Acc AC	-273 to 200°C	High reliability Ageing stability Versatility (2) High volume production Low cost Numerous option (5)	Lower resolution than PZT ceramic (4)	General absolute laboratory Acceleration measurements. Cryogenic application.
Quartz	Charge	Acc AC	-273 to 200°C	Very high reliability Ageing stability	Lower resolution than PZT ceramic (4)	Absolute laboratory Acceleration measurements Cryogenic application.
PZT Ceramic			-55 to 260°C	Very high reliability High resolution	Less stable than quartz	Industrial vibration measurements in high temp. environment
BT Ceramic			-55 to 500°C	Very high reliability High resolution compares to tourmaline	Less stable than tourmaline	Industrial vibration measurements in very high temp. environment
tourmaline or eq.			-273 to 800°C	Very high reliability	Very expensive	Industrial vibration measurements in very high temp. environment

(1) ®ICP is a worldwide voltage transmission standard that uses a constant current source supply. Some manufacturers still offer proprietary current transmission which is not useful for standard application: AC acceleration up to 10 kHz and 500 meters, AC velocity up to 5kHz and 1000 meters, displacement up to 1kHz and 2000 meters.

(2) The AC acceleration signal can be externally conditioned to have concomitamment AC velocity, AC displacement, DC acceleration, DC velocity or DC displacement.

(3) With no AC acceleration output, you will not be able to connect a portable analyzer with envelopping algorithm for roller bearing defect detection.

(4) Resolution is important if you plan to make measurements at low frequency (<10Hz) with vibration parameters like velocity or displacement.

(5) This type of sensors covers the broadest range of characteristics: few grams to kilograms, epoxy or hermetically sealed, large choice of connector, top or side connector,.....

general purpose, premium

The most versatile, they use piezoceramic in the annular shear mode and provide Acceleration AC output.

They usually sense vibration commonly find in industrial machinery : motors, fans, pumps, paper machine rolls, ....

general purpose, economy

They use piezoceramic in the compression mode and provide Acceleration AC output.

They usually sense vibration commonly find in industrial machinery : motors, fans, pumps, paper machine rolls, ....

low frequency

They use piezoceramic in the annular shear mode and provide AC acceleration output with increased sensitivity (500mV/g).

They are used when low frequency measurement down to 0.1 Hz is necessary to balance or evaluate mechanical condition of low speed machinery : cooling towers, low speed agitators, hydromachinery, structural testing, ...

high frequency

They use piezoceramic in the annular shear or compression mode and provide acceleration AC output with reduced sensitivity (10mV/g). They are used for modal testing or when very high frequency measurements up to 20-30kHz are needed.

high temperature , ©ICP mode

They use piezoceramic in the annular shear mode and provide AC acceleration output up to a temperature of 150°C.

multi output

They provide acceleration and/or velocity and/or temperature output.

 

Description

The hermetic sealed industrial piezoelectric accelerometer model 101 is design to monitor the vibration in harsh industrial environment. It uses the industry standard ©ICP 2-wire voltage transmission technique with a 4 mA standard constant current supply. Signal ground is isolated from the mounting surface and outer case to prevent ground loops. Faraday shielding will limit sensitivity to EMC to a minimum. Annular shear mode design will prevent from thermal transient and from spurious signal from high transverse vibrations. Low noise electronic and a temperature compensated design will give you accurate result over the complete temperature range. Large choice of frequency range will help to fit almost every customer requirements. Low frequency accelerometers (A=9 & 0) incorporate a low-pass filter within the conditioning electronic. This filter attenuates the sensor mechanical resonance and the associated distortion and overload.

Typical applications

Vibrations measurement in the rugged environments of industrial machinery monitoring. High frequency version monitor the vibration on roller bearing, pumps cavitation, .... Medium frequency version monitor overall vibration on pumps, motors, fans, ... Low frequency model is used in the petrochemical, machine tool, and paper industries for monitoring of slow speed agitators, cooling towers, ... High temperature version is typically used where extra temperature protection is needed, such as the dryer section of a paper machine.

Ordering information. Low, Medium, high frequency.

To order, specify model number, options and suffix :

101.01- A - B - C - D (Accessories)

A : Sensitivity

*3 : 10 mV/g (high frequency)
*6 : 100 mV/g (medium frequency, general purpose)
*9 : 500 mV/g (low frequency)
0 : 1000 mV/g (Very low frequency)
Available suffix : N, negative polarity

B : Connector

1 : MIL-C-5015, glass seal
*2 : M12 glass seal
3 : M12 epoxy sealed

C : Agency approval

*0 or omitted : CE approval

D : Sensor thread

*0 or omitted : M6
7 : 1/4" 28 UNF 2A

Accessories :

M2 : 10-32 UNF 2A mounting stud
M5 : M5x0.8 mounting stud
M6 : M6x1 mounting stud
M7 : 1/4" 28 UNF 2A mounting stud
M8 : M8x1.25 mounting stud

Special Engraving :
Add ZXX at the end of the part number.
XX is a number supplied by VibraSens

 

 

Ordering information. High Temperature.

High temperature version is only available with A=6 and B=1.

To order, specify model number, options and suffix :

101.11- 6 - 1 - (Accessories)

* Popular model (in stock) :

101.01-3-2 / 101.01-6-2 / 101.01-9-2 / 101.11-6-1

Ordering example :

101.01-6-2M6M7 Accelerometer, piezoelectric

 

Specifications (24°C)

Dynamic

Sensitivity A=3 10 mV/g ±5% A=6 100 mV/g ±5% A=9 500 mV/g ±5% A=0 1000 mV/g ±5%

Frequency response fig. 4a, 4b A=3 ±10 % : 1 to 11000 Hz ±3 dB : 0.5 to 16000 Hz A=6 ±10 % : 1 to 9000 Hz ±3 dB : 0.5 to 14000 Hz A=9, 0 ±10 % : 0.4 to 1600 Hz ±3 dB : 0.2 to 3700 Hz

Mounted Resonant frequency

A=3 35 kHz Nom A=6 25 kHz Nom A=9, 0 16 kHz Nom

Dynamic range

A=3 500 g pk A=6 80 g pk A=9 10 g pk A=0 5 g pk

Transverse response sensitivity (20Hz, 5g) <5%

Temperature response fig3

Polarity (fig. 1) Suffix dependant

Linearity ±1% Max

Warm up time A=3, 6 < 1Sec A=9, 0 < 10 Sec

Electrical

Electrical Grounding Isolated from machine ground

Internal Faraday shielding (fig. 1)

Isolation (Case to shield) 100 MΩ Min

Capacitance to ground 70 pF Nom

Output impedance 50 ΩNom

DC output bias , 4mA supply 12 VDC (Fig 2)

Residual noise (24°C) : A=3

1 Hz to 25 kHz 300 ug rms

1 Hz 30 ug

Residual noise (24°C) : A=6

1 Hz to 25 kHz 300 ug rms

1 Hz 30 ug

Residual noise (24°C) : A=9

1 Hz to 25 kHz 25 ug rms

1 Hz 2.4 ug

Power requirements Constant current : +2 to +10mA DC Voltage : +22 to +28 VDC

Protection : Overvoltage Yes

Protection : Reverse polarity Yes

Environmental

Temperature : Operating continuous : 101.01 B=1, 2 -55 to 120 °C (-65 to 250 °F) B=3 -55 to 90 °C (-65 to 194 °F) A=9 -55 to 100 °C (-65 to 212 °F) A=0 -55 to 80 °C (-65 to 176 °F)

Operating continuous : 101.11 (max. current =4mA) B=1 -55 to 150°C (-65 to 302 °F)

Humidity / Enclosure B=1, 2 Not affected, hermetically sealed, 1E-8torr.l/s B=3 Not affected, epoxy sealed

Acceleration limit : Shock 5 000g peak

Acceleration limit : Continuous vibration 500g peak

Base strain sensitivity 0.0002 g pk/u strain

Temp. transient sens. (3Hz, LLF, 20dB/dec) 5 mg/°C

Acoustic sensitivity (164 dBSP) 0.5 mg

Electromagnetic sens. (50Hz, 0.03 T) 0.2 g

Mean time between failure (MTBF) 10 Years Nom

ESD Protection > 40 V

Safety EN 61010-1 and IEC 1010-1

EMC emission EN 50081-1, EN 50081-2

EMC immunity (1) EN 50082-1, EN 50082-2

Physical

Dimensions B=1 Fig. 1a B=2, 3 Fig. 1b

Design Ceramic, preloaded annular shear mode

Weight , A=3 80 gr Nom (2.8 Oz)

Weight, A=5, 6 85 gr Nom (3.0 Oz) Weight, A=9, 0 95 gr Nom (3.4 Oz)

Connector B=1 MIL-C-5015 glass seal, Type MS3143 10SL-4P B=2 M12 glass seal, IEC 60947-5-2 B=3 M12 epoxy seal, IEC 60947-5-2

Material AISI 316L, DIN 1.4435 (Stainless steel)

Mounting M6x1 tapped centre hole

Mounting torque (M6, M7, M8 suffix) 2,4 N.m (21 in-lbs)

Accessories, supplied

Calibration supplied Sensitivity (5g, 160 Hz) No frequency response

Accessories, not supplied

Cable assembly B=1, Polyurethane cable 10.01-B01-A01-01-Length B=1, FEP Teflon cable 10.01-B01-A01-02-Length B=2, 3 Polyurethane cable 10.01-E01-A01-31-Length B=2, 3 FEP Teflon cable 10.01-E61-A01-02-Length PU or FEP Armored cables are also available. See Model 10.01.

Mounting Stud M6 191.01-06-06-1 1/4" 28 UNF 191.01-06-16-1

Repair : Consult factory for replacement of connector in case of broken or bended pins. Repair of electronic is not possible

(1) Guaranted if using accessories listed in this product datasheet only

 

Fig 1a : Outline drawing & Electrical layout, B=1

Fig 1b : Outline drawing & Electrical layout, B=2, 3

Fig 2 : DC (Bias) deviation versus temperature

Fig 3 : Sensitivity deviation versus temperature

Fig 4a: Frequency response, amplitude

Fig 4b : Low Frequency response, amplitude

Due to the continual development of products, VibraSens reserves the right to modify these specifications without forewarning. PNR:500022.01 - September 18, 2006 - Released A.B.

®ICP is a registered trademark of PCB Group, Inc., Depew, New York

 

Competitive advantage

• Annular shear mode is less susceptible to transverse vibrations and better immune to electronic saturation at high frequency
• Exceptional bias voltage stability at elevated temperatures.
• Low cost IP67 overmolded M12 cable assembly
• M12 overmolded cable assembly is available through local electronic distributor
• M12 offers compatibility with sensors used in automation

Description

The hermetic sealed industrial piezoelectric accelerometer model 103 is design to monitor the vibration in harsh industrial environment. It uses the industry standard ®ICP 2-wire voltage transmission technique with a 4 mA minimum constant current supply. Signal ground is isolated from the mounting surface and outer case to prevent ground loops. Faraday shielding will limit sensitivity to ESD to a minimum. Annular shear mode design will prevent from thermal transient and from spurious signal from high transverse vibrations. Low noise electronic and a temperature compensated design will give you accurate result over the complete temperature range. Large choice of frequency range will help to fit almost every customer requirements. Low frequency accelerometers (A=9) incorporate a low-pass filter within the conditioning electronics. This filter attenuate the sensor mechanical resonance and the associated distortion and overload.

Typical applications

Vibrations measurement in the rugged environments of industrial machinery monitoring. High frequency version will monitor the vibration on roller bearing, pumps cavitation, .... Medium frequency version will monitor overall vibration on pumps, motors, fans, ... Low frequency model is used in the petrochemical, machine tool, and paper industries for monitoring of slow speed agitators, cooling towers, ...

 

Ordering information. Low, Medium, high frequency.

To order, specify model number, options and suffix :

103.02- A - B - C - D (Accessories)

A : Sensitivity

*3 : 10 mV/g (high frequency)
*6 : 100 mV/g (medium frequency, general purpose)
*9 : 500 mV/g (low frequency)
0 : 1000 mV/g (Very low frequency)
Available suffix : N, negative polarity

B : Connector

1 : MIL-C-5015, glass seal
*2 : M12 glass seal
3 : M12 epoxy sealed

C : Agency approval

0 or omitted : CE approval

Accessories :

M6 : M6x1 Bolt, captive, hex socket
M7 : 1/4" 28 UNF 2A Bolt, captive, hex socket

Special Engraving :

Add ZXX at the end of the part number.
XX is a number supplied by VibraSens

Ordering information. High Temperature.

High temperature version is only available with A=6 and B=1.

To order, specify model number, options and suffix :

103.12- 6 - 1 (Accessories)

*Popular model (in stock) :

103.02-6-2 / 103.02-9-2 / 103.12-6-1

Ordering example :

103.02-6-2M6M7 Accelerometer, piezoelectric

 

Specifications

Dynamic

Sensitivity A=3 10 mV/g ±5% A=6 100 mV/g ±5% A=9 500 mV/g ±5% A=0 1000 mV/g ±5%

Frequency response fig. 14a, 14b A=3 ±10 % : 1 to 9000 Hz ±3 dB : 0.5 to 13000 Hz A=6 ±10 % : 1 to 6000 Hz ±3 dB : 0.5 to 10000 Hz A=9, 0 ±10 % : 0.4 to 1600 Hz ±3 dB : 0.2 to 3700 Hz

Mounted Resonant frequency

A=3 32 kHz Nom A=6 22 kHz Nom A=9, 0 16 kHz Nom

Dynamic range

A=3 500 g pk A=6 80 g pk A=9 10 g pk A=0 5 g pk

Transverse response sensitivity (20Hz, 5g) <5% max

Temperature response (See fig13)

Polarity Suffix dependant

Linearity ±1% Max

Warm up time A=3, 6 < 1Sec A=9, 0 < 10 Sec

Electrical

Electrical Grounding Isolated from machine ground

Internal shielding

Isolation (Case to shield) -55°C to +120°C 100 MΩ Min

Capacitance to ground 70 pF Nom

Output impedance 50 ΩNom

DC output bias , 4mA supply 12 VDC (See Fig 12)

Residual noise (24°C) : A=3

1 Hz to 25 kHz 300 ug rms

1 Hz 30 ug

Residual noise (24°C ): A=6

1 Hz to 25 kHz 300 ug rms

1 Hz 30 ug

Residual noise (24°C): A=9

1 Hz to 25 kHz 25 ug rms

1 Hz 2.4 ug

Power requirements Constant current : +2 to +10mA DC Voltage : +22 to +28 VDC

Protection : Overvoltage Yes

Protection : Reverse polarity Yes

Environmental

Temperature : Operating continuous : 103.02 B=1, 2 -55 to 120 °C (-65 to 250 °F) B=3 -55 to 90 °C (-65 to 194 °F) A=9 -55 to 100 °C (-65 to 212 °F) A=0 -55 to 80 °C (-65 to 176 °F)

Operating continuous : 103.12 (max. current =4mA) B=1 -55 to 150°C (-65 to 302 °F)

Humidity / Enclosure B=1, 2 Not affected, hermetically sealed, 1E-8torr.l/s B=3 Not affected, epoxy sealed

Acceleration limit : Shock 5 000g peak

Acceleration limit : Continuous vibration 500g peak

Base strain sensitivity 0.0002 ug pk/u strain

Temp. transient sens. (3Hz, LLF, 20dB/dec) 5 mg/°C

Acoustic sensitivity (164 dBSP) 0.5 mg

Electromagnetic sens. (50Hz, 0.03 T) 0.2 g

Mean time between failure (MTBF) 10 Years Nom

ESD Protection > 40 V

Safety EN 61010-1 and IEC 1010-1

EMC emission EN 50081-1, EN 50081-2

EMC immunity (1) EN 50082-1, EN 50082-2

Physical

Dimensions B=1 See Fig. 1a B=2, 3 See Fig. 1b

Design Ceramic, preloaded annular shear mode

Weight 103.02

A=3 150 gr Nom (5.2 Oz) A=6 155 gr Nom (5.6 Oz)

A=9, 0 165 gr Nom (6.0 Oz)

Connector 103.02 B=1 MIL-C-5015 glass seal, Type MS3143 10SL-4P B=2 M12 glass seal, IEC 60947-5-2 B=3 M12 epoxy seal, IEC 60947-5-2

Material AISI 316L, DIN 1.4435 (Stainless steel)

Mounting torque (M6, M7 suffix) 2.4 N.m (21 in-lbs)

Accessories, supplied

Calibration supplied Sensitivity (5g, 160 Hz) No frequency response

Accessories, not supplied

Cable assembly B=1, Polyurethance cable 10.01-B01-A01-01-Length B=1, FEP Teflon cable 10.01-B01-A01-02-Length B=2, 3 Polyurethance cable 10.01-E01-A01-31-Length B=2, 3 FEP Teflon cable 10.01-E61-A01-02-Length PU and FEP Armored cables are also available. See Model 10.01.

Mounting Stud M6 193.01-06-1 1/4" 28 UNF 193.01-16-1

Repair : Consult factory for replacement of connector in case of broken or bended pins. Repair of electronic is not possible

(1) Guaranted if using accessories listed in this datasheet only

Fig 12 : DC (Bias) deviation versus temperature

Fig 13 : Sensitivity deviation versus temperature

Fig 14a : Frequency response, amplitude

Fig 14b :Low Frequency response, amplitude

 

Fig 1a : Outline drawing & Electrical layout, model 103.02-A-1

Fig 1b : Outline drawing & Electrical layout, model 103.02-A-2,3

 

Due to the continual development of products, VibraSens reserves the right to modify these specifications without forewarning. PNR:500022.03 - September 18, 2006 - Released A.B.

®ICP is a registered trademark of PCB Group, Inc., Depew, New York

Description

The sealed industrial piezoelectric accelerometer model 105 is design to monitor the vibration in harsh industrial environment. It uses the industry standard ©ICP 2-wire voltage transmission technique with a 4 mA standard constant current supply. Signal ground is isolated from the mounting surface and outer case to prevent ground loops. Faraday shielding will limit sensitivity to EMC to a minimum. Low noise electronic and a temperature compensated design will give you accurate result over the complete temperature range.

Economy compression mode accelerometers should not be used whenever thermal transient, high transverse vibrations or high base strain are present. Compression accelerometers are also not recommended for low frequency (<1Hz) measurements. In such environments model 101 (annular shear mode) is prefered.

Typical applications

Vibrations measurement in the rugged environments of industrial machinery monitoring. High frequency version will monitor the vibration on roller bearing, pumps cavitation, .... Medium frequency version will monitor overall vibration on pumps, motors, fans, ...

Ordering information

To order, specify model number, options and suffix :

105.01- A - B - C - D (Accessories)

A : Sensitivity

*2 : 100 mV/g ±10%
*3 : 10 mV/g ±10%
Available suffix for A : N, negative polarity

B : Connector

1 : MIL-C-5015, glass seal
2 : M12 glass seal
*3 : M12 epoxy sealed

C : Agency approval

0 or omitted : CE approval

D : Sensor thread

*0 or omitted : M6
7 : 1/4" 28 UNF 2A

Accessories :

M2 : 10-32 UNF 2A mounting stud
M5 : M5x0.8 mounting stud
M6 : M6x1 mounting stud
M7 : 1/4" 28 UNF 2A mounting stud
M8 : M8x1.25 mounting stud

Special Engraving :
Add ZXX at the end of the part number.
XX is a number supplied by Vib