... range 1.2~220mm 2.auto null point calibration,sound velocity measuring 3.data storage/inquiry/deletion 1 ... , anemometer, sound level meter, noise meter, vibration meter, ultrasonic thickness gauge, film/coating thickness gauge, digital hygrothermograph, high ... measuring lower limitΦ20*3mm(steel)auto null point calibration, system error correctionlinear auto compensation, correct nonlinear error ...