The aftermarket grip for the ATI MB3R shotgun forend fits Picatinny rails. The tactical shotgun foregrip simply installs on any picatinny rail on your tactical shotgun forend and you're done. The shotgun vertical foregrip has a palm swell and a high-tech texture with a slip-resistant finish for excellent handling and hand support. The end cap conceals storage for most of the needed accessories and parts. Grip is made of an impact-resistant advanced polymer that has been molded to be unbreakable. Overall width is 2 1/4". The vertical height is 4 1/2". It fits on any MIL-STD-1913 picatinny rail on tactical shotguns and the AR-15 rifle picatinny rail handguard. Picatinny rails are sold separately.