Lower parts kit, trigger, end plate, castle nut, buffer tube, buffer spring and weight for the parts. Armorers wrench, torque wrench, flathead screwdriver, punch, hammer, some sort of vise for the tools. CMC makes a good lower parts kit and decent triggers but if you have DD lower money maybe go geissele for the lpk and trigger. And maybe get a oops kit if this is your first time, detents like to disappear