Summary This lets you make a connection from a 1/2" poly hose to a tank. Instructions You'll need to add a garden hose washer so that it won't leak. Print it with a 100% infill, otherwise the bottom of the connector may break off as you tighten down the nut. Update - I uploaded a slightly newer version (v05) that makes the area around the washer a little thicker, the hole in the middle a little smaller (so that the walls are thicker), and the nut a little smaller (so it puts less pressure on the threads when you tighten it down). A regular hose washer still fits it but you'll need to push to get it over the last bit of plastic. It is a lot stronger now but you should still only hand tighten (snug but not too tight).