By far, Marble’s® #20 Universal Rear Sight is the most versatile barrel mounted sight available today. The system combines a strong, sleek uni-base with both peep and U-shaped semi-buckhorn uprights to accommodate the individual shooting styles of any hunter. Both the windage and elevation adjustments have evenly spaced graduation lines and screw tension locks it down in both directions. You can be very precise while sighting in. Once set, these sights are rock solid and will hold up to the roughest use. All of the components are CNC machined from solid steel—no castings, no stampings.   Marble’s® has designed one of the most versatile barrel-mounted fiber optic rear sights that can be used on modern rifles, slug shotguns, and muzzleloaders. The brilliantly glowing fiber optics are 100% protected in our reflector channels so you can walk through dense brush without fear of damaging the optic cables. You can make precision adjustments for both windage and elevation with a small screwdriver. The sight is available in all standard barrel contours, flat for octagon barrels or ribs, and a variety of heights. Marble’s® fiber optics are UV protected for long life. >>Universal Rear Sight Specifications