The Radian Weapons Guardian Optic Guard for Glock MOS offers an unparalleled optic mounting solution for your pistol. Engineered from durable 7075 aluminum this black frame guard ensures your Trijicon RCR optic remains securely in place. The innovative TRUSEAL technology eliminates the need for additional sealing plates by using O-rings on the mounting screws creating a watertight seal to prevent moisture and corrosion. With the advanced STUDLOK threaded studnut interface enjoy superior thread engagement enhanced hold-down strength and increased shear resistance making it the most reliable system available for Glock MOS users.