UTG Pro Forerunner 15in M-LOK Free Float Handguard Black. Forged AR15 Upper Receivers Compatibility with Billet Upper Receivers is Not Guaranteed Barrel Nut Fits Over Barrel Diameters up to 1.05in Actual Length from Flush with Receiver to Furthest End of Handguard 6.75/9.75/13.75/15.25/17.25/4.75in Package Contents: UTG Pro Forerunner M-LOK Free Float Handguards M-LOK Picatinny Rail Section QD Sling Swivel Adaptor Installation Hardware Barrel Nut Wrench UTG Pro MTU047SPM: UTG PRO Forerunner 15in M-LOK Free Float Handguard Black