The Advanced Technology AR-15 military buffer tube assembly package fits most AR-15 and AR variants. It features a 6-position, hard-coat anodized 6061-T6 aluminum buffer tube with mil-spec thread diameter of 1.19" and mil-spec tube diameter of 1.15". This assembly also comes with an AR-15 recoil plug, buffer spring, and a steel, military Grade E-coated castle nut and locking ring. Features: Military diameter threads for maximum fit into AR-15 receiver Constructed of military type III anodized, 6061 T6 aluminum Includes steel military grade E-coated castle nut and locking ring Includes AR-15 recoil plug and buffer spring Virtually indestructible Limited lifetime warranty Made in USA