Williams Regular Rear Sight Aperture 1/2" Diameter 0.093" Hole

Williams apertures are standard thread size and will accommodate Williams, Redfield and Lyman receiver sights. The Twilight series are designed for shooting under poor light conditions. They create a sharp contrast that gives quick definition to the aperture hole. Big Game aperture is designed to mount on the FP or 5D receiver sight and has an extremely large opening, similar to a ghost ring type of sight.