Brand new model for the Clippard Mini-Matic Valve (R-331, R-501, R-701, etc) as many models out there are incorrect in the mount-hole spacing.
This model is based on Clippard's own drawings plus measurements of an 80's Vintage R-331, and is visually the same as every other Mini-Matic valve - just affix the appropriate label.
Includes two knobs, one screwed all the way in, one screwed all the way out.
Small liberties were taken with the font on the front for printability. This might be best printed by a nozzle < 0.4mm and layer height under 0.2mm. I got it to come out OK by slowing the printer down.