Replaces OEM scope cap with 35Adeg offset mounting surface, for optics with common Trijicon RMR footprint. Two bosses and two #6-32 threads. Right-handed. Includes pocket for spare 5.56 AR extractor spring to place upward pressure on CR2032 battery on Gen 1 Trijicon RMR Fits Geissele Super Precision and Reptilia AUS 34mm / 0 MOA mounts. 1.535" height. Bore concentric with M4 upper receiver. RMR sits .25" higher than primary optical axis *Red Dot Not Included*