A crank-driven moon phase display. Set it on a desk or bookshelf and turn the side crank: the two-piece ball advances one click at a time through eight lunar phases, from new moon to full and back. A tactile display piece for astronomy fans, teachers, or anyone who wants the moon's cycle within reach.

How the crank turns the moon. Turn the crank knob at the side and the arm carries that motion into the axle behind the frame. The axle spins the two-piece ball and its detent clicks into each of eight stops, so one turn brings up the next lunar phase instead of drifting past it.

Fit and finish. The two hemispheres meet along a single tight seam, so the ball reads as one smooth sphere in hand. Standing about 3.3 inches tall with a 2.8 by 2.5 inch footprint, it sits comfortably within reach on a desk, and every surface, from the base to the crank knob, carries the same fine, even layer lines.

What's in the set. Eight pieces make up the set: base, base hatch, rear C-frame, axle with detent, crank arm, crank knob, and the two dome halves that join to form the sphere. The axle runs through both domes and up into the C-frame, the crank arm attaches to the axle, and the hatch fits into the base.