It is a sleeve that snaps into the 1" hole where the hot end, extruder and layer fan wires go through. I couldn't get the heat shrink supplied with the kit to shrink enough so it would stay above the hole and it has since slipped down slightly. I will be adding some split loom on top of it, but I figured having a smoother edged surface can't hurt to help prolong the wire insulation from wearing.I used ABS but PLA should work just fine. Print at 1:1 scale with the lipped side against the hotplate. I used no support and had no issues with the print. You can install it from the top or the bottom of the machine; I chose from the bottom to eliminate any disassembly. Place the lipped edge on the top surface so it cannot fall through the hole and that is it.