SummaryMount a dial Gauge inside your Thing-o-Matic so leveling the print bed is easy. Mounts to the Mk7 extruder plate.InstructionsThis is designed to be used with this dial indicator (http://www.amazon.com/gp/product/B000NPPBVK?psc=1&redirect=true&ref_=oh_aui_detailpage_o00_s00). The clearance hole is 6 mm, the sleeve is 11 mm. Shim in the dial indicator to get a tight-fit. I used a twisty-tie. Use some of your favorite M3 nut adapters and m3 screws to attach it to the plate.