MRP-L QUAD 5.56MM ASSEMBLED UPPER RECEIVER The patented LMT Monolithic Rail Platform, MRP(TM) upper receiver. The receiver and handguard are made from a single piece of forged aerospace aluminum. The barrel is held in place with a proprietary locking system that utilizes two locking bolts accessible from the right side of the receiver. The only tool needed is a standard T-30 Torx bit to tighten the bolts. This receiver requires the patented LMT monolithic barrel assembly which has a low profile gas block with straight gas tube. The MRP-L QUAD 9.25 is the carbine length receiver designed for 10.5a ^2 barrels up to 18a ^2 barrels with quad rail at the 3, 6, and 9 o' Mfg: Lmt Defense