... Different application, DC 3 wires, DC2 wires or AC 2 wires.TK series square shape inductive ... Inductive type, sensitive to metal; 2) Square sensing face, with different dimension; 3) Optional current output, ... ; 5) Different application, DC 3 wires or AC 2 wires.TC series column shape capacitive ... Capactive type, sensitive to different material, including metal or non-metal; 2) Current output 200 mA; 3 ...