I wanted a way to be able to carry small rotary tool bits on the TTTTT without them just being chucked into the box to rattle around and not be found! Thinking about it I designed a quick slot on 3d printed part that had some holes to receive rotary tool bits. It needed a couple of iterations as I made the holes to shallow in the first attempt. It now holds the rotary tools well with them sat in a 24mm deep hole. The slot is a loose sliding fit so it has some retention when the TTTTT is being carried but it can be slid along the walls or removed really easily. I plan to make a couple of other accessories using this approach at some point, a through holed screwdriver holder and perhaps a small lidded tray for holding screws.