0.4 Nozzle Wall Thickness Calibrator

If you, like me, design and print at set wall thicknesses this may be of interest. This is designed for a 0.4 nozzle but can work for 0.2 as well. The aim is to run it at 4 perimeter/1.6mm thick and then use callipers to measure the actual thickness of the parts.
NOTE: The last is 1.5mm and not 1.6mm as that's a personal preference and I use it to print 3mm solids and engineering strength parts. Your slicer may turn it into 1.5 or 1.6 depending on the algorithms and its useful to know which!