Features Known thickness, sound speed can be measured, in order to improve the measurement accuracy; Coupling status indicator showing the coupling status; EL backlight for easy use in dimly lit environments; Remaining battery indicator can display the remaining power in real time; Auto sleep and auto power off function to conserve battery life;Specifications Measuring Range: 0.75-300mm/0.03inch~11.8inch (Depends on probes) Working Frequency: (2.5-7）MHZ Probe Diameter: Standard N05 is10MM、Probe N07 is 6MM、Probe HT5 is12MM、Probe N02 is12MM Min. Pipe Diameter: Φ15mm×2.0mm/Φ0.59inch×0.08inch Resolution: 0.1mm/0.004inch Accuracy: ±（0.5%Thickness+0.04）mm,depends on probes Display: 4.5 digits LCD with EL backlight Single /Scan Mode: Four measurements readings per second for single point measurement, and ten per second for Scan Mode Probe Calibration: Zero Calibration, Two-Point Calibration Velocity Range: 1000-9999m/s Unit: Metric/Imperial unit selectable Language: English Memory: up to 20 files (up to 99 values for each file) of stored values Power supply: Two “AA” size, 1.5 Volt alkaline batteries(not include) Lower Power Comsumption: Yes Working Hours: 100h (EL backlight off). Operating Temperature: －20℃～＋60℃ Relative Huminity: ≤90％ Appearance: ABS Plastic Outline dimensions: 5.9×2.9×1.26 inches Gross Weight: 3.3lb Note Due to shipping policy, couplant and batteries are not included