Lengths: 7, 9, 12.375 & 15 inches Tube: Patented carbon fiber braid Caps: Aluminum Barrel Nut: Standard Free Float w/ Jam Nut (included) You can install this handguard right out of the box! Want to add some accessories? No worries, check out the Brigand Arms 2.5" Picatinny Rail Segment, sold separately. Allows you to add as few or as many accessories as you'd like while maintaining a lightweight rail. It comes with a special backing plate to make sure any accessories you add remain secure at all times. Mfg: Brigand Arms