Handheld Ultrasonic Thickness Gauge Steel Aluminium Plate Thickness Meter PVC AS850. Auto calibration to assure the accuracy. Auto linear compensation: this advanced software program enhances the precision by correcting the non-linear accuracy of transducer. Make a quick adjustment for the sound velocity / thickness, and a quick recall to the stored data. Coupling status indication: Observing the coupling icon to learn if the coupling is accomplished or not. 10 thickness measurement storage and recall function available, which facilitates the height work or working in wild area. 12 sound velocity for different material which is also adjustable. More than 10000 times long life keys. Largr LCD display for easy readout. Low battery indication and auto power off. The unit has a unique memory that retains all of its settings even when the power is off. Measuring Range: 1.2220mm(steel). Minimum display unit: 0.1 mm. Mininum limit for tube measuring(steel): 20 3.0mm(steel). Sound velocity Range: 10009999m/s. Operation temperature/humidity: 0 to 40. Power supply: 3 1.5V AAA alkaline batteries (not included). 1 Ultrasonic Thickness Gauge. 1 10mm 5HZ Transducer. 1 4mm Sampling Block. (Without Gel and Battery). If you can not find the coupling agent at your local store, you can use the detergent or oil instead, but please do not wash in water. You can clean by cloth or paper. To avoid the rusty. The standard package don’t include batteries. Thanks for your support! Appreciate your kind understanding. Thank you for your cooperation!