The Patented US Patent No. D671,611 Gear Sector Rail Mount Hand Stop was designed to provide a low profile, ergonomic solution for increased weapon control. We designed them to fit perfectly flush with the Tango Down rail panels for an uninterrupted rail space. They can be mounted anywhere on a picatinny rail but work best when run in pairs. A bottom stop allows the weapon to be pulled into the shoulder pocket and a side mounted stop indexes perfectly in the web of your hand for proper placement behind a weapon mounted flashlight. Specifications for American Defense Manufacturing Rail Mount Hand Stop - Mod 3: Manufacturer: American Defense Manufacturing Color: Black Features of American Defense Manufacturing Rail Mount Hand Stop - Mod 3 The Gear Sector Rail Mount Hand Stop is precision CNC machined from billet 6061-T6 aluminum and finished in Cerakote. Material: 6061-T6 Aluminum Finish: Cerakote MilSpec Green ( H-264 ) Weight: 0.6 ozs. Package Contents: American Defense Manufacturing Rail Mount Hand Stop - Mod 3