The cam is indexed to allow repeatable, adjustable flow control. There are probably more compact designs possible, but I wanted to optimize this for ease of use and long-term reliability.   Source files included for those who'd like to modify them for other tubing sizes.Works in PLA, though use the slipperiest PLA you have for best usability. Other plastics will probably work well too, but make sure your layer bonding is on point. Designed for printing with 2mm walls all around and no infill.