I have seen these small test tube looking doohickeys being supplied from many chinese suppliers, but never with any description as to what they are for. They almost invariably have the description "Automatic Filling Tube Liquid Test Tube With Spout" which didn't lead me anywhere.
With most glassware, even relatively complex pieces, I can usually discern what it is for and why it is designed in that way but this has me stumped. My best guess so far is that it is meant to collect liquid from a sealed flask where the long stem passes through a bung to the bottom of the flask and gas pressure pushes some liquid up and into the tube. So maybe it is for volumetric reagent dispensing? If you had a squeeze bulb on the bottle it would push liquid up into the tube, then suck back and reduce the level to a consistent volume, but you would have to tip the whole bottle to pour it out so idk?
If anyone is familiar with what these are for and how they are used it would be much appreciated because this has been bothering me for a while.