Aero Precision AR15 15in ATLAS S-One M-LOK Handguard - Black - The ATLAS S-ONE is the newest addition to the Aero Precision Handguard lineup. Machined from 6061-T6 Aluminum, the S-ONE line of handguards are designed with size and weight in mind, providing the perfect handguard for your lightweight build. The 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. 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 1.3in Inside diameter 1.5in Outside diameter Compatible with mil-spec AR15 upper receivers and barrels NOT Compatible with M4E1 Enhanced Upper Receivers