This sealing plate for Trijicon's RMR allows for your optic's battery compartment to have better resistance to being submerged in water.
The seal should be used if the mounting surface is interrupted, has any through features, or the mounting surface does not fully encompass the sealing boundary. RMRs are slightly wider than the slide (except for G21/G20 slides). These ensure your Type 1 or Type 2 RMR rubber gasket is properly sealed against the slide.
