​​​​​​​we Have Three Models ULTRASONIC THICKNESS GAUGE AS840 AS850 AS860 Let Me What Difference

 Model 

 AS840

 AS850

 AS860

 Display

 4-digital LCD display

 4-digital LCD display

 4-digital LCD display

 Minimum display unit:    

 0.1 mm

  0.1 mm 

  0.1 mm

 Measuring Probe:

 ∅10mm 5MHz

 ∅10mm 5MHz

 ∅10mm 5MHz

 Measuring range

 1.2 to 225.0mm (steel)

 1.2~225mm(steel)

 1.00 to 300.0mm(steel)

 Working frequency

 5MHz

 5MHz

 5MHz

 Accuracy

 (1%H+0.1)mm,H denotes
the measured thickness.

 ±(1%H+0.1)mm,H denotes
the measured thickness.

 ±(1%H+0.1)mm,H denotes
the measured thickness.

 Minimum limit for tube measuring

 20*3mm (steel)

 20*3mm (steel)

 20*3mm (steel)

 Sound velocity range

 1000 to 9999 m/s 
Measuring sound velocity with a given thickness: measuring range:  1000 to 9999 m/s.
When the given thickness >20mm, the accuracy is +/-5%;
when the given thickness <20mm, the accuracy is +/-1mm/H*100%.

 Operation temperature

 0℃ to 40℃

 0℃ to 40℃

 0℃ to 40℃

 Relative humidity:    

 <90%RH

 <90%RH

 <90%RH

 Hardware/workpiece/material temperature:

 <60°C

 <60°C

 <60°C

 Power supply

  3 * 1.5V AA Battery(Not Included)

  3 * 1.5V AA Battery(Not Included)

  3 * 1.5V AA Battery(Not Included)

 Operation current: 

 Normal operation current: 50mA
With Backlight turn on current: 120mA  Stand-by current: 20uA

 Normal operation current: 50mA
With Backlight turn on current: 120mA  Stand-by current: 20uA

 Normal operation current: 50mA
With Backlight turn on current: 120mA  Stand-by current: 20uA

 Product Weight

 152g

 155g

 191g

 Product Size

 161x66x31mm

 160 x 66 x 32mm

 163 x 70 x 34mm  

 Package Weight

 670g

 880g

 850g

 Package Size

 25x21x6cm

 29.5 x 19.5 x 7cm

 29.5 x 19.5 x 7cm

 Packing Contents

 1 * Ultrasonic Thickness Gauge
1 * Φ10mm 5MHz Transducer
1 * 4mm Sampling Block
1 * Storage Box
1 * User Manual

 1 * Ultrasonic Thickness Gauge
1 * Φ10mm 5MHz Transducer
1 * 4mm Sampling Block
1 * Storage Box
1 * User Manual

 1 * Ultrasonic Thickness Gauge
1 * Φ10mm 5MHz Transducer
1 * 4mm Sampling Block
1 * Storage Box
1 * User Manual

Table of sound velocity   (Sound velocity of common materials)

Material

Velocity(m/s)

Material

Velocity(m/s)

Aluminum

 6320

Acetate resin 

2670

Zinc

4170

Phosphor bronze

3530

Silver

3600

Turpentine

4430

Glod

3240

Glass

5440

Tin

3230

 Incoloy alloy

5720

 Iron/Steel

5900

Magnesium

6310

Brass

4640

Monel alloy

6020

Copper

4700

Nickle

5630

SUS

5790

Steel 4330 mild

5850

Acrylic resin   

2730

Steel 330

 5660

Water 20C 

1480    

Titanium

6070

Glycerinl

1920  

 Zirconium     

4650

Soluble glass

2350 

Nylon 

2620