The Geissele Posi-Lock Ambidextrous safety is made from 400 series stainless steel, and features Geissele's Posi-Lock design that offers a very positive and tactile feel as the safety snaps into position when engaged by the operator. The Geissele Posi-Lock Ambidextrous safety greatly improves longevity and performance over its mil-spec counterpart. Mfg: Geissele Automatics Llc