Original WW2 production 1918A2 gas regulator. Used, cleaned, gauged to be serviceable USGI WW2 production gas regulator with key, modified for use in semi automatic Ohio Ordnance Works 1918A3 SLR. These are used, surplus regulators and will show varying surface condition, cosmetic blemishes or other non functional issues. Includes the retention key. For use on gas tubes with 3 slots, and not the postwar modified single slot type.