1、Reliable accuracy, it can automatically zero calibration to ensure accuracy. When the given thickness is greater than 20mm, the accuracy is ±1%; when the given thickness is less than 20mm, the accuracy is ±5%. 2、Coupled with indicator light, it can prompt in time to ensure correct measurement. 4 digits LCD digital display, it can be used for thickness measurement. 3、Data storage and memory function, it can carry out 10 groups of thickness measurement storage, which is more convenient for recording and measurement. 4、Multifunctional use, it can measure the speed of sound of a certain thickness, and also measure various materials, including steel, copper, aluminum, glass, plastic, ceramics, resin, polyvinyl chloride, water, etc. 5、Small in size, portable and lightweight, it can be easily held for measurement in various situations. Item Type: Thickness Gauge Model: GM130 Material: ABS Battery: 3x1.5V AAA Battery (Battery Not Included) Purpose: It can be used for thickness measurement. LCD Digital Display: 4 Digits Minimum Display Unit: 0.1mm Working Frequency: 5MHz Measuring Range: 1-300mm (Steel) The Minimum Measurement Limit of The Tube: 20mm / 0.8in Diameter, 3mm / 0.1in Thickness. Accuracy: ±(1%H+0.1mm) (H represents the measured thickness.) Sound Speed Range: 1000~9999 M/S Measuring Range: 1000~9999m/S Operating Temperature: 0~40°C (32~104°F) Normal Working Current: ≤50mA Standby Current: ≤20μA 1 x Ultrasonic Thickness Gauge (Battery Not Included) 1 x Transmitter (5MHz) 1 x Transmitter (5Pφ10) 1 x 4mm Iron Sample 1 x Manual