Amtech's 4 piece converter set is made with chrome plated hardened carbon steel.

The set includes sizes: 1/2"(F) x 3/8"(M), 3/8"(F) x 1/4"(M), 3/8"(F) x 1/2"(M) and 1/4"(F)x3/8"(M).

Please note they are not suitable for use with corded, cordless or pneumatic impact drivers.