New in wrap Colt bolt carrier group. Current production. These are guaranteed to have C marked carriers and MPC marked bolts. Markings may be rollmarked stamped or dot matrix stamped. No choice of markings. New in the factory Colt MIL STD sealed poly bag. These are the same Colt bolt carrier groups which have come in all factory Colt rifles since 2008, if you need to rebuild your rifle. These are compatible with both semi auto only and select fire rifles.