The universal fit Gen 1 AR-15 Easy Jig® is a patented router jig that makes machining your 80% lower easier, faster, and safer by utilizing a router instead of a drill press. The Easy Jig® allows you to complete an 80% lower in about 1/3 the time it takes to complete a lower on an old style drill press jig. This 80% lower receiver router jig is easy enough for a caveman to use. It definitely lives up to its name. You also save money on tools. You do not need to own a drill press, mill, or any measuring tools to use the Easy Jig®.  The Easy Jig® is built like a tank (weighs over 6 lbs) and can be reused for dozens of lower receivers.