My wife is an avid runner and obstacle cource racer. She almost always carries a hydration pack. This little tool is useful to help drying out her bag after cleaning and rinsing it out, to avoid mold and other nasty things to settle in the bag.

I'd strongly recommend printing this in PETG, but likely it's fine too with PLA. PETG is just friendlier for anything that touches food or other consumables.