Timber Creek Castle Nut, Black

Ergo Castle Nut for AR-15, Black - 4971-(B)

Tacfire Buffer Tube Castle Nut for AR-15 - Black, Essential for Assembly - MAR039

JP Enterprises Enhanced Carbine Buttstock Castle Nut, Black

SONS OF LIBERTY GUN WORKS Castle Nut, Class 3A Thread

LBE AR15 CASTLE NUT

ARMASPEC ARM6521-ODG SELF-RETENTION CASTE NUT/AL

CMMG Barrel Nut, Black - Essential Component for Secure Barrel Installation and Reliable Performance - 55DA244