An eighty percent lower receiver is a lower receiver which has not been deemed a firearm by ATF criteria. An eighty percent lower receiver is the most complete a receiver is usually without having the ATF considering it a firearm. Glock® 43 Compatible Pistol Establish Kit w/ Black Slide To https://dantewkqbi.sharebyblog.com/31604431/getting-my-polymer-80-glock-43-complete-kit-to-work