Diamondhead VRS T-Threaded 556-13 Free Float Handguards 13.5 in. offer an uninterrupted rail extension and handguard in perfect alignment with the host weapons flat top receiver. The VRS T rail replaces the factory delta ring and barrel nut. The VRS Free Floating Handguard System provides excellent flexibility of use by adding accessory rails and bumpers to the VRS for the required rail-mounted accessories. NOTE: Requires removal of both delta ring and factory barrel nut and replacement of front sight with low profile gas block.