This is a bracket to hold a depth gauge to the extruder head of an ultimaker 3d printer. This allows easy and quick levelling of the build table. The bracket is sized to fit a gauge I found in a box of junk in my loft. The gauge measures deflection to an accuracy of 1/1000 of an inch, so in theory I can get my build table that level. In practice, I probably get 1/200 of an inch, but that's easily accurate enough to improve my prints.Print the bracket and the flange, and drill the holes. The small holes should be M3, the larger hole on the flange should be sized to fit whatever bolt fits your gauge. Once you have drilled the holes, superglue 2 nuts (with washers) to the base - see the pics for clarification. this allows quick removal of the flange with gauge still attached, for printing. The base can then be fitted to the long bolts that form the structure of the extruder assembly. Fit it on the opposite side to the fan. The dial gauge should be bolted to the flange, and the flange can then be bolted to the base - and you're good to go.Once you've levelled the build table, you'll need to remove the flange with the gauge still attached (leaving the base still fixed the the extruder head). Otherwise the gauge will hit the side of the printer during the print.I printed this at 30% infill, layer thickness 0.2mm or so.