Perfect for that situation where you need the versatility of a magnified optic paired with a Trijicon red dot sight in close quarters. This offset rail adapter attaches to the firearms picatinny rail and provides a short picatinny rail at a 45 offset to mount a red dot sight. Ambidextrous for Right or Left Handed Shooters. This is just the rail adapter. In order to mount the Trijicon RMR or SRO you will also need the RM33 Low Mount.