This is a Marbles Arms tang sight (aka Peep Sight) Browning model 1892, model 53 and model 65 rifle. It comes with 3 different sight apertures (1/2 inch diameter with .055 hole; 1/2 inch diameter with .102 hole; 3/4 inch diameter with .032 hole). Hole spacing on the base of the sight is .375 inches and the height adjustment is 2.000 inches TO 2.265 inches. Height adjustment is 1.680 inches to 2.015 inches, with an 18 degree angle. Mounting screws are NOT INCLUDED with the tang sight, so if you need those screws they can be purchased in the option box below.