This is an ID100 Stock adapter to allow the installation of a real stock onto your ID100 body kit. It is not recommended for adding a stock to other body kits, especially fragile 3D-printed body kits. It can be used as a quick strip bolt cap for any Emek or Etha 2 (with any body kit).
The adapter replaces the stock bolt guide cap and is indexed and then bolted to the ID100 body kit from above with two 10-32 bolts and one longer lower bolt that replaces the rear grip frame screw.