It is Modelled in OpenSCAD not at all elegant or but it works. The extra tabs were added to stop the sheild from popping out on shake test Sliced in Slic3r with 2 perimeters an no infill at all. This means that the stand off is a bit flexible and possibly more comfortable even when printed in ABS. Printed on an old reprap mendel with a 1mm nozzle, can get a layer height of 1.1mm without losing solidity. Speed has to be reduced to 12mm/s for my manky old extruder, still gets print done in 10mins. You can modify the standoff to cope with goggles by changing the os parameter in OpenSCAD file. There are some calulations to get a 2 thread thick wall at the top of the file, this normally does rectangle plus 2 semicircle thread model but has been fudged for the abnormal layer height. So if you change the nozzle and layer height you will also need to change the build width. That soulds confusing (sorry).