These are a couple of 2x4 Gridfinity bins designed to hold the spindle for the Genmitsu Cubiko when it's out of the machine, whether that's to use the alternate (high speed) spindle, the laser, the drawing tool, or during maintenance. The center part of the bin is sized to keep the spindle in place, but the upper end is extended so that if you've modded your spindle to use an XT30 connector, there's room for the pigtail.

Two bin models are available, labeled for the two currently available Cubiko spindles.

I printed mine with 20% infill, no supports, in basic black PLA.