1Auto calibration to assure the accuracy. 2Sound velocity measurement: with a given thickness to measure the sound velocity to improve accuracy. 3Large LCD display for easy reading. 4Low battery, auto power off function, etc. 5Used in the field or work at heights Features: 1.Auto calibration to assure the accuracy. 2.Sound velocity measurement: with a given thickness to measure the sound velocity to improve accuracy. 3. Large LCD display for easy reading. 4. Low battery, auto power off function, etc. 5. Used in the field or work at heights Specification: Condition: 100% Model: GM100 Measuring Range:1.2-225mm(steel) Accuracy:(1%H+0.1mm) H denotes the measured thickness Working Frequency:5MHz Resolution:0.1mm Minimum Limit for Tube Measuring(steel):dia. 20*3.0mm(steel) Sound Velocity Range:1000-9999m/s Color: Orange Power Supply:3 * 1.5V AAA Battery(not included) Weight: Approx. 400g / 14.1oz Size: Approx. 15 * 8 * 3.2cm / 5.9 * 3.2 * 1.3in Package List: 1 * Ultrasonic Thickness Gauge 1 * Dia.10 Transducer(5KHz) 1 * 4mm Sample Block