EGW red dot sights are meant to be installed from the left to the right (with the muzzle facing forward). The dovetail has a progressive taper to allow for easier install. Simply remove the rear sight on your gun and replace it with EGW mount in order to mount your Vortex Viper/Venom, Burris FastFire, or Docter red-dot sight. You can take the mount off and replace your rear sight at any time. Mounting hardware included. Minor modification may be neccessary for Rock Islands. EGW products should be installed and checked by a qualified and competent gunsmith. Installation Instructions Remove the rear sight* Install the EGW Sight Mount in the dovetail Tighten set Mfg: Egw