A hex bit holder for the smaller 4mm hex bits. Can be screwed to a wall & also the mounting holes align with the holes of a pegboard with 25mm hole spacing. The holes are initially a tight fit for the bits but are soon loosened up by reinserting a bit many times. Holds 56 bits and driver handle + extension.
See also two other versions for ¼" hex bits -
https://makerworld.com/en/models/436028#profileId-341129
https://makerworld.com/en/models/438635#profileId-344143