4mm Adjustment Knob and Nut Lock Plate
This knob fits nicely on top of a 4mm screw to allow fine adjustments without a pesky allen wrench. The nut Lock plate allows you to loosen the nut and then lock down when you are done adjusting.
I use this on my Fusematic volume rebuild to adjust the z-axis. When I switch from printing on 3M tape back to glass only, its an easy switch because I know where the knob needs to be.