The RE-1 receiver extension allows you to mount a Mil-Spec stock on a civilian carbine or convert your A2 style fixed buttstock to a collapsible configuration. This receiver extension has five positions and corresponding white position numbers that are visible through the witness hole on most stocks.
VLTOR RE-1 Stock Black Receiver Extention AR-15 RRE-1
WARNING: This product may contain chemicals known to the State of California to cause cancer and birth defects or other reproductive harm. For more information, go to www.P65Warnings.ca.gov