This big sight has a tiny square notch centered in a flat section surrounded by tall buckhorns. The dovetail base is .490" long, .720" wide. Dovetail 0.050" deep. Height from the bottom of the dovetail to the top of the sight notch is 0.39". It may be file fitted to smaller slots. Use this large buckhorn rear sight on an 1-1/8" octagon rifle barrel. This part replaces the RS-PA-237 shown in older catalogs.