The Williams™ 71030 Fire Sight is specifically designed to fit the Ruger SR 1911. Williams™ Fiber Optic Fire Sights offer shooters unmatched open sight visibility in low light settings. The fiber optic rods built into every Williams™ Fire Sight Set gather ambient light and reflect it back to your eye, enabling faster target acquisition. Williams™ Fire Sights do not use artificial light sources to create their sight visibility, making them legal to use in states that do not allow artificial light sources on your firearm while hunting.