The TDI Arms X6 is the World's First 6-Rail System for M16/AR15/M4. It
provides a 100% secure fit that does not restrict barrel movement and
adds 4 MIL-STD 1913 handguard Picatinny Rails and 2 Front Sight mini
rails. A 7th adjustable rail may be added (Sold separately). CNC
machined of billet aviation grade aluminium; the X6 is easy to fit and
requires no gunsmithing. Included are 2 long and 6 short heat
resistant rail covers. The X6 is NTOA (National Tactical Officers
Association) member tested and recommended.