The Regulated Bolt Carrier (RBC) is a lightweight carrier with a gas regulating gate built into the carrier itself. This provides a drop in, lightweight solution for those looking to tune your AR-15's gas system. It eliminates the need for adjustable gas blocks, and allows the firearm to be restored to a factory full weight system by simply swapping your full-mass carrier back into your firearm. The RBC has infinite adjustment from fully open, to fully closed on the regulating gate. The RBC can be tuned to most combinations of buffers, springs, suppressors, and barrel lengths. The RBC Is fully adjustable through the port door, and does not require the firearm to be broken down&nb Mfg: 2a Armament