The 80% Arms universal drill press AR-15 jig consists of 5 individually replaceable plates that show you where to drill or mill your lower. We recommend it as a more cost effective option for more experienced users who already own a drill press. For those looking for the simplest fastest system to complete a lower we highly recommend our router based Easy Jig™ system. - Our universally compatible drill press jig makes finishing your 80% lower at home with a drill press or mill much easier. Every part of this jig is reusable and can be used to make dozens of lowers. This AR-15 jig is NOT compatible with our .308 lowers or Easy Jig tool kit.