TRUGLO TRUBEAD Universal Series 3 Dot Sights for Ventilated Rib Shotguns The industry's most popular fiber-optic turkey sight series-now with DUAL-COLOR front sight option Universal mounting system for ventilated rib shotguns with ribs up to 3/8" Front sight includes different sized "clips" to eliminate twisting; full windage and elevation adjustment; CNC-machined Hardware included; includes two interchangeable rear sights; endorsed by The National Wild Turkey Federation Model TG950XD, front diameter is 0.12", rear diameter is 0.035"; Model TG950X, front diamter is 0.06", rear diameter is 0.035