Z18 Rear mount spool holder

I wanted a spool holder that would allow me to put the tops back on my Z18 printers. At first I planned to drill holes in the side of the cabinet but then I took notice of the slots already cut into the rear. After printing, just hold it in place and mark two spots to dill 4mm holes and use two machine screws and nuts. They sag a little when you put the 1Kg role on but they have held up well. Sits average black roles w 54mm hole.