Measuring range: 1.2~225mm (Steel) Accuracy: (1%H+0.1) mm Resolution: 0.1mm Sound velocity range: 1000~9999m/s Working frequency: 5MHz Minimum limit for tube measuring: 20*3mm (Steel) Operation Current: Normal operation current<=50mA, with backlight turn on current: <= 120mA, standby current: <=20uA Auto calibration to assure the accuracy Auto linear compensation: this advanced software program enhances the precision by correcting the non-linear accuracy of transducer. Data store/ Data recall/ Data delete function Sound velocity measurement Low battery indication Auto power off LCD backlight display Power supply: 3pcs*1.5V AAA alkaline batteries ( No included ) Weight: 210g Dimension: 70*145*28mm Package Content: 1 x GM100 Ultrasonic Thickness Gauge ( No including the retail box or battery )