The Mega GTR-3H Billet AR-15 Upper Receiver comes stripped and ready for your next custom AR build. ZEV starts with high-quality 7075 T6 aluminum billets and final machines them to better than mil-spec dimensions held to .001 tolerances, giving you maximum compatibility with mil-spec and aftermarket parts and accessories. The Mega GTR-3H Billet AR-15 Upper Receiver offers superb strength and versatility for building an AR-15 configured exactly the way you want it. Technical Specs Machined from Forged American Made 7075-T651 billet aluminum True Black Class 2 Type 3 Hard Coat Anodize Compatible with all Mil-Spec parts kits T marked picatinny rail M4 feed ramps cut standard Shipping Information NOTE: Item cannot be shipped to Illinois