This is a mini "bubbler" for a 55mm anti-spill "water cooler" jug, to let air into the bottle while water leaves in a controllable way. It does not have a valve of its own, just a hose barb.It prints in three parts, the core, the reservoir, and the hose barb. The reservoir and hose barb attach to the core with ABS cement. It WORKS -- but may be wasteful of plastic, the reservoir sometimes overtops briefly, and the flow rate isn't terrific. It uses O-rings to seal the bottle to it, and fits surprisingly tightly. Improvements I intend for the next version: 1) A "peak" on the top, to get the inside cap out of the way of the inlet. 2) A taller reservoir, better-sealed at the top. 3) Wider and shorter internal plumbing 4) Some way to turn the stupid thing off I don't post source on Thingiverse anymore, so you'll find the SCAD on bld3r: http://www.bld3r.com/obj/5847440401891328