The new HS507C Micro Red Dot System from Holosun is a pistol-sized optic with an open frame for a great sight picture, clear glass and a rugged 7075 aluminum housing. It is powered by a CR2032 battery and Holosun’s innovative Solar Fail-safe back...
Use the Trijicon sealing plate with the RMR to keep dust and moisture out of your optic. 
Trijicon RMR, 3.25 MOA, Type 1, Adjustable LED, Black Finish
Trijicon RMR, 3.25 MOA, Type 2, Adjustable LED, Black Finish Enhance your shooting experience with Trijicon. Add speed and precision and speed to your self-defense, duty weapon, competition or target pistol with an RMR or with an upgrade to your stock...