A well designed, graceful, peep sight with a traditional flair, cast in *brass*. The sight's screw holes are countersunk to hide the screw heads of the two 6-48 thread MOUNTING SCREWS that ARE INCLUDED. Dimensions are 3 1/2" long X .35" wide and the base is 1/16" thick. Not adjustable for elevation, however, the front screw hole is egg shaped to allow a little bit of side to side adjustment by loosening the screw, moving over, and re-tightening it. There are two sizes of apertures available from Muzzleloader Builder's Supply. The larger is .093 (#21210) for quick target acquisition (or tired eyes), and the smaller .050 (#21200) to limit the field of view for target shooting. Hole spacing is .550". Iron. (Top of barrel to sight center is 7/16").