1. Auto calibration to assure the accuracy.2. Coupling status indication: Observing the coupling icon to learn if the coupling is accomplished or not.3. 10 thickness measurement storage and recall function available, which facilitates the height work or working in wild area.4. Sound velocity measurement: With a given thickness by sample hardware to measure the sound velocity, which avoids the further conversion or consultation of the table.5. 12 sound velocity for different material which also adjus- table.6. Low battery indication7. Auto power off mode designed to conserve battery life.8. More than 10000 times long lift keys.9. The unit has a special memory that retains all of its setting even when the power is off.10. Power supply: 3 X 1.5V AAA batteries(Not included)Specification: Package Weight One Package Weight 1.01kgs / 2.23lb One Package Size 20cm * 15cm * 5cm / 7.87inch * 5.91inch * 1.97inch Qty per Carton 24 Carton Weight 25.30kgs / 55.78lb Carton Size 42cm * 32cm * 22cm / 16.54inch * 12.6inch * 8.66inch Loading Container 20GP: 901 cartons * 24 pcs = 21624 pcs 40HQ: 2093 cartons * 24 pcs = 50232 pcs