After overwhelming requests to solve the ever growing problem of forgotten magazines, Andrew Bobro of Bobro Engineering, designed the F.N.G.R. to prevent misplacement of your magazine. F.N.G.R. is designed to retain your firearm's magazine in the confines of your lower receiver to prevent loss or theft.
Fits on most AR-15/AR-10 style firearms and others utilizing a standard AR-15 magazine catch. Certain AR-15 billet and AR-10 lowers may require fitting of the F.N.G.R. shim due to smaller recesses in the magazine well.