... 2 mm - 220mm (Steel, conventional probe) 2.0.8mm-50mm(Small tube thickness probe) UTM-101H ultrasonic thickness gaugefeatures:According to ... .Linear automatic compensation, using single-chip microcomputer software correct probe error and with high accuracy.Measuring scope: 1.2 ... mm - 220mm (Steel, conventional probe) Or 0.8mm-50mm (Small tube thickness probe)4 digit LCD display, can backlit ...