This Baldwin Hardware 8231 single cylinder deadbolt is intended for doors with a 2-1/8" bore hole. This Baldwin deadbolt is constructed of solid brass for strength and smooth operation. Baldwin 8231 deadbolts feature an extended hardened steel insert for maximum protection and security. Meets ANSI Grade 1 requirements. Please call (866)259-8901 if you have any question or would prefer to order by phone. We are here to help!