Simple mount which can be glued directly to the packing clips that secure your extruder head when you unpack machine, these were made to measure and a perfect fit so why re invent the wheel. One short M3.5 machine screw and nut to secure not really necessary at first but after several uses could be needed. A dab of either Super glue, 99% Acetone or PVC/ABS pipe weld to attach the printed plate to retaining clips. Sized to fit the Silverline 0-10mm Metric Dial Indicator which I obtained from amazon for under £8 makes calibration a doddle.