Aero Precision APAR538105M45: The S-ONE line of handguards are designed with size and weight in mind, providing the perfect addition to your lightweight build. Aero Precision\'s proprietary ATLAS attachment system is a durable and dependable mounting platform, maintaining a slim profile while still providing the strength and stability customers have grown to love from Aero Precision handguards. This complete upper does not include a BCG or Charging Handle. Includes: M5 Assembled Upper Receiver ATLAS R-ONE Handguard of choice 20\" 6.5 Creedmoor SS Barrel, Rifle Length Low Profile Gas Block and Rifle Length Gas Tube Product comes assembled M5 Assembled Upper Features: Forged from 7075 T6 aluminum M4 Feedramps .2795 takedown pin holes Laser engraved T-marks DPMS High Profile (.210) Tang) Includes port door and forward assist ATLAS S-ONE Handguard Features: Front and rear picatinny rail Eliminated center of top rail for weight reduction Indexing grooves in 12:00 position for positive grip control Quick disconnect sling socket at the 3, 6 and 9 o\'clock positions Compatible with low profile gas blocks 1.5\" Inside diameter 1.75\" Outside diameter Compatible with AR-308 Upper Recievers with a thread pitch of 1-7/16 x 16 along with a DPMS High Profile (.210) Tang Rail 20\" 6.5 Creedmoor Stainless Steel Barrel Features: Twist: 1 in 8 Threading: 5/8 x 24 Material: 416R Stainless Steel Finish: Bead Blasted Gas Block Journal: .875 Gas System Length: Rifle Length Weight: 66.1 oz DPMS Barrel Extension HP and MPI Tested