These sights will only work on a Ruger Mark III and 22/45 that DO NOT have the Ruger logo stamped on the rear stock sight. If you DO have the Ruger stamped on the rear stock sight, these sights will NOT work. Please search for item 71054. These fiber optic sights will make your buddies jealous the next time you go to the range. They collect surrounding light rays to offer you superb visibility even in dark conditions. Features bright green fiber optic rear dots and a bright red fiber optic front dot that will give you a crisp, clear sight picture. Super easy installation as well. Speed up your target acquisition and improve your accuracy today with Williams FireSights. Will work with the following MKII and MKIII Ruger models: 22/45 Competition 22/45 Government Target 22/45 Target 22/45 Hunter Competition Government Target Target Hunter Bull Barrel Slabside.