Sniper&reg; Snap-on FO Fiber Optic Front Sight Kit Plain Barrel Shotgun - 12/20 Gauge; Choice Green Red Light Pipe Snaps on, no tools required. Fits just behind bead sight Excellent addition to any 12 or 20 gauge shotgun Easy to see in daylight and low light conditions Improves your shooting Does not work with ribbed/ventilated barrels - plain barrels only