Shield Arms Item Number: SA-15-SLUBillet 7075-T6 Aluminum AR-15 Stripped Lower ReceiverBuilt-In Folding Mechanism - Not an AdapterMulti Caliber MarkedCaliber: .223/5.56, .300 BLK, 6.5mm Grendel, 7.62x39mmPrecision Machined Magazine Well with Beveled Feed LipCompatible with Most Standard AR-15 Components and Aftermarket PartsTake Down Pin Spring and Detent Hole Threaded for a 6-32 Set Screw (hardware included)Upper Tension Screw Behind Grip Screw (threaded hole with hardware included)Threaded Bolt Catch Pin (threaded hole and hardware)Mil-Spec 8625 Type 3 Class 2 Hard Anodized Matte Black FinishWeight: 12.4