TangoDown Rail Grips offer superior impact and easy installation on Mil-Standard 1913 weapon system rail fore ends. They may be placed anywhere on the rail (depending on rail length). The aggressive texture allows a positive grip on the weapon even in wet or muddy conditions. The BP-4S is 6" in length. 'Binary' Aggressive Texture Superior Heat and Impact Resistance Locates Anywhere on Mil-Standard 1913 Rail Systems Length: 6" Weight: 1.28 oz Inside Diameter of Switch Pocket: 0.653" w/SureFire Inside Diameter of Switch Pocket: 0.93" w/ITI