Requires an M3 thumbscrew and nut (heat-set). I printed with 100% infill in PETG. Supports should only be necessary on the bottom wafer, under the slot. The registration marks print fine without supports.

Holds your pricking irons an adjustable distance away from the edge of whatever you're poking holes into. Also helps keep your irons plumb and makes pulling them out much easier.

You adjust the stitch offset by loosening the screw and sliding, and the height by adding or removing the thin wafers.