The 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. Designed to mount to Glock MOS for Holosun HS507 Comp optic. 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 resistance. SIX back-up sights (BUS) seamlessly integrate into the Guardian Optic Mounting System providing rapid reliable and precise target acquisition in scenarios of red dot optic malfunction. Featuring anti-glare anti-snag and ultra low co-witness design SIX sights lie inconspicuously in wait until you need to deploy them. Like a wingman when things aren’t going as planned SIX has your six.