For the lower you will need blue masking tape (to prevent any scratches while installing roll pins), a punch set (roll pin punch set makes it MUCH easier), a brass hammer (doesn't mar the lower), a small regular hammer for the punches, a block of wood to support the lower, a long allen wrench for the screw that holds the grip, and a wrench for the castle nut on the buffer tube. You can get the cheaper wrench for $5 on Amazon if you are just building the lower. You'll want an armorer's wrench if you are building the upper too. I like to use a razor blade to hold the detent in place while I install the takedown pins. Oh, and I install the detents while holding the lower in a box. Those things disappear in a hurry. The zip lock bag is a good one too.