LBE Unlimited Complete F Marked Front Sight Base, Taper Pins, Sight Post, Detent, Spring, Swivel, and Swivel Rivet ARFSB-KIT LBE Unlimited is a quality manufacturer of AR-15 parts and accessories. The Complete F Marked Front Sight Base comes with Taper Pins" Sight Post" Detent" Spring" Swivel" and Swivel Rivet.