OPEN BOX / BLEMISH These items are discounted because they have been used or have blemishes in the finish. Other than the finish these items are fully functional. Our 15 inch free float quad rail handguard installs on standard AR-15 rifles, extending beyond the front gas block and further down the barrel. The four Picatinny rails allow for the attachment of tactical accessories such as bipods, grips, or sights. The free float handguard attaches directly to the receiver, without touching the barrel or impacting barrel harmonics, thus allowing for more precise shooting. Available in black and flat dark earth.Note that the aluminum barrel nut is significantly lighter than steel barrel nuts, however it may be subject to damage during installation. We recommend using no more than 35 pounds of torque during installation. Please note that installation of a free float handguard requires additional gunsmithing tools and expertise. For questions regarding fitment or installation, please refer to our AR-15 quad rail guides and installation guides. Includes: Free float quad rail handguard, aluminum barrel nut, castle nut, anti-rotation set screw, Allen wrench. Materials: 6061 Aluminum Alloy Compatibility: Not Compatible with Bushmaster Carbon 15 rifles serial number E18000+ unless Bushmaster barrel nut is used. Weight: 1.4 lbs Length: 15 in Height: 2.5 in Internal Diameter: 1.7 in Color: Black or Flat Dark Earth Warranty: Lifetime