The included ATLAS R-ONE Handguard is designed with size and weight in mind, while still providing plenty of real-estate to accommodate any attachment needs the end user may have. Our 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.
THESE DO NOT INCLUDE A BCG OR CHARGING HANDLE, AS PER NORMAL AERO PRODUCT NAMING CONVENTION
Includes:
M4E1 Threaded Upper Receiver
15" ATLAS R-ONE Handguard
16" 5.56 CMV Barrel
Low Profile Gas Block and Mid-Length Gas Tube
Port Door Assembly
A2 Flash Hider
This complete upper receiver does not include BCG or Charging Handle. 
M4E1 Threaded Upper Receiver Features:
Custom enhanced forging that gives the upper receiver a "billet look" while maintaining the structural integrity of a forged part.
Picatinny profile that blends seamlessly with our Enhanced and ATLAS Series Handguards
M4 Feedramps
.250 takedown pin holes
ATLAS R-ONE Handguard Features:
Full top picatinny rail for optional attachments
Quick disconnect sling socket at the 3, 6 and 9 o'clock positions
1.3" Inside diameter
1.5" Outside diameter
Compatible with mil-spec AR15 upper receivers and barrels
MLOK attachment points
16" 5.56 Barrel Features:
5.56 NATO 16" Barrel, 1/7 twist, 4150 CrMoV, QPQ, gas port drilled
.750 gas block journal
Mid length gas system, .0785 gas port
M4 Feed Ramp Extension
HP and MPI tested
Standard A2 flash hider