This Aero Precision EPC-9 Complete Upper Receiver comes standard with the ATLAS R-ONE Handguard. The R-ONE handguards are designed with size and weight in mind, while still providing plenty of real-estate to accommodate any attachment needs the end user may have. 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. FeaturesLast round bolt hold open mechanismStandard AR15 takedown/pivot pin lug patternMachined from custom forged 7075-T6 aluminumFull top picatinny rail for optional attachmentsQuick disconnect sling socket at the 3, 6 and 9 o'clock positions