M5 ATLAS Handguards are incredibly SLIM. How slim? Their 1.5" inner diameter makes them one of the thinnest on the market. The R-ONE and S-ONE handguards give you the versatility to choose between modularity and profile, and when you factor in the ATLAS attachment system, you have the lightest and most dependable handguard that you'll find for the AR-308. Get your's today!