This is a snap on gauge holder for precise bed leveling. I liked the idea behind the dial gauge holders that I'd seen for Ultimaker, but had a few additional requirements: - No chance of accidentally ramming the gauge into some other part of the printer. - Quick, tool-free attachment and removal of the gauge. - Usable with a large display digital gauge. I picked up an AccuRemote Digi Depth gauge with extension rods from 1 to 5 inches in length. I use the 4 inch rod and the gauge clip to check the bed next to each leveling screw whenever I have to remove the bed. The larger diameter side of the clip snaps onto the extension rod and the smaller side snaps onto the long studded bolt nearest the print nozzle. Move the nozzle next to each screw in turn and press the gauge down. Adjust leveling screws and repeat as needed.