M-Lok sling adapter short base or long base with 1 1/4" push button QD swivel so you can quickly attach or detach slings. (if you want 1" swivel, just ask) OR D shape short base or long base 1) Short base 22mm centres 2) Long base 33mm centres 3) D short base 22mm centres 4) D long base 33mm centres * select which one you want.