F.A.B. Defense TAL-4 Tactical Vertical Foregrip, Fits Picatinny Rails, Black FX-TAL4B The TAL-4 Tactical Vertical Foregrip is designed to provide improved hold on your weapon and more comfortable use of pressure switch activated devices with the dual sided optional slots. Includes an internal water resistant storage compartment for batteries or small parts. Attaches to any Picatinny rail interface.