16x16mm and 20x20mm stacks are starting to show up with M2 holes. With this kit you get M2x18mm cap head steel botls, M2 nylon nuts and M2 nylon threaded spacers. This should be everything you need for a 2 board stack.
Post your build using this product to RotorBuilds.com and it will show up here! Awesome :-)
Complete builds using this part: