This is a cover to hold a thermistor against the top of your glass surface for measuring the bed temperature. This little thing will create a pocket to shield the measurement from ambient air or fans. It also protects it from physical damage. I figured why measure at the PCB when what you really want to know is the temperature of your printing surface. In my case, this is a plain glass sheet. (1/8" or 3mm window pane) I use a 100k thermistor; the kind with both insulated leads on the same side. If you use the honeywell kind that looks more like a regular resistor with leads coming out of opposing sides, you'll want to rotate the cutout for the leads 90' in the scad file.1. Print shroud at 0.3 layer height or smaller. 2. Insert thermistor leads through the shroud from the bottom 3. Seat the thermistor in the hole. 4. Use a binder clip to hold the shroud against your glass. Optional: Squirt some thermal paste on/around the thermistor from the bottom of the shroud for even more accuracy.