Atlas Bipods Tube Rail Kit-2.05in 1913 Rail Nut plate and 2 screws for free float tubes Black. 050" long with a 1.00 radius back and 1.602 between the two holes and two fasteners. This TUBE RAIL KIT is installed with the Steel Bar Nut inside the free float tube and the 1913 Picatinny rail on the outside with the matching holes aligned fastened together they allow the attaching of the BT10 or BT10-LW17 Atlas Bipod or other accessories to free float tubes. Specifications for Atlas Bipods Tube Rail Kit-2.05in 1913 Rail Nut plate and 2 screws for free float tubes: Manufacturer: Atlas Bipods Color: Black Country of Origin: USA Package Contents: Atlas Bipods Tube Rail Kit-2.05in 1913 Rail Nut plate and 2 screws for free float tubes Atlas Bipods BT33 Tube Rail Kit-2.05in 1913 Rail Nut plate and 2 screws for free float tubes Black