1.LCD display 2.Easy to carry 3 ... DSP chip, have fast measurement ability Descriptions:AT-220,AT-230, AT-240 these instruments use magnetic thickness measurement ... and hard-magnetic steel, etc.) without damage.AT-220F,AT-230F these instruments use vortex thickness measurement method, ... calibration and two points calibration.6, Wide angle LCD display7, Units conversion of metric and British system8, ...