Marble Arms tang sight (aka Peep Sight) Marlin 39AS, 1894 CB and CB II, 1894S, and CS-1897 CB AND the Glenfield model 30 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 .500 inches center to center, and the height adjustment is 1.680 inches to 2.015 inches with a 18 degree angle on the upright. Mounting screws are NOT INCLUDED with the tang sight, so if you need those screws they can be purchased in the option box below. Additional screws can be purchased (see part No. 995015).