Radian Weapons H0016 Guardian+Six Black Compatible w/Glock MOS, Trijicon RCR FootprintThe GUARDIAN is the strongest optic mounting system on the market. TRU SEAL eliminates the need for an added sealing plate. 0 rings on the mounting screws hold the plate watertight to the slide, sealing out moisture, eliminating corrosion in the mounting threads. Our STUD LOK threaded stud nut mounting interface is the most secure system on the market. This provides much longer thread engagement, greater hold down power, with increased shear