Visible 4mm Hex Bit Holder

This is a bit holder I designed to work with my ES121 screwdriver, though it'll work with any screwdriver that takes 4mm hex bits. The only special accommodation for the ES121 is that the spacing is set to fit the head. I wanted something where I could switch the bits directly, and still see which was which without needing labels.

The bits push in from the top or from the side, and there's enough friction to pull them out of the screwdriver - to remove them you put the screwdriver on them then pull them off sideways. So you never actually handle the 4mm bits again, the screwdriver pulls them out and puts them in.

I know it looks simple, but this thing has massively improved my disassembly work and speed on electronics and small mechanical devices like 3D printers with a few different small screw types.