Stag Arms upper, BCG, and charging handle, piston drive with adjustable gas block,16" barrel, 1-7" twist, Diamondhead free float handguard, Yankee Hill Phantom flash hider, around 250 rounds no barrel heat up, no mag dumps, 2" groups @ 100 yards with red dot. Note: Stag Arms has a life time barrel replacement to who ever owns it. $300.00 + half shipping can email or text pictures