Shelf pin jig used for drilling consistent holes for ajustable shelves in a cabinet.
Its designed to use the Milescraft 5mm self centering bit.
https://www.amazon.com/gp/product/B00TSA3RC6/
I wanted a design that the final size was larger than the bed on my x1c, so I split the model with a dovetail.
The design also includes two pins to help locate the jig when moving down the cabinet face.