F.A.B. Defense Foregrip and Spare Magazine Holder, Fits Picatinny Rails, Accepts AR-15 Magazines, Black FX-MG20B The MG-20 is a 2-in-1 foregrip and spare magazine holder" enhancing tactical efficiency by accommodating an additional magazine in hand and facilitating swift magazine changes. It accepts any standard AR-15 magazine and attaches to an M1913 Picatinny rail interface.