The 2A Armament(TM) Xanthos rails continue the tradition of an extremely lightweight"" rugged"" and quality rail to complement the 2A Armament Xanthos-lite receiver set and the .308 handguard market. Two different styling choices are available"" a traditional Balios inspired design (XRVC-15)"" and a more progressive slant cut design (XRSC-15). The aluminum barrel nut"" with 2A's innovative 45 degree set screw mounting system provides an easy to install"" solid joint to the upper receiver with no protruding fasteners or sharp edges.