The ‘secret ingredient’ of IDC technology is the unsupported cantilever ‘U’ contact. This is a precision stamped part made of metal alloy. Beryllium copper (BeCu) is used in 3M™ IDC Wiremount Socket, 3000 Series. BeCu has the lowest stress relaxation rate, high resistance to corrosion, extremely good wear resistance and better electrical conductivity than either brass or bronze. Phosphor bronze is used in the 891 Series from 3M. Phosphor bronze is excellent for applications requiring relatively few insertion/withdrawing (or ‘mating’) cycles and low contact flexure.