Stockpile Defense SD1 lower receivers are manufactured for us by our friends over at PWS. We needed a M4 style, simplistic, yet properly done lower for LE/Agency contracts so we asked for a variance and they did it! What makes them so great, you ask? Well, it’s the machining quality you come to expect from something with the SD logo on it. And, because it’s made by PWS, you know they’re held to tight tolerances with great quality controls. These lowers are a perfect way to start a new build off. They come complete just like you would see with a factory PWS lower. They will even include a PWS Enhanced buffer tube, PWS buffer, PWS ratcheting castle nut/end plate, and a much better than mil-spec polished Nickel Teflon trigger. Finished off and anodized per Mil-Spec (MIL-A-8625F) which is a Type III Class 2 hard anodizing process. Machined right here in Boise from USA forgings! Do not hesitate to build your next gas or piston upper off of these beautiful lowers.