KIPRUN 1l dryer

Compared to the original drying hook this prevents germs to fall down inside the bag.
The gadget simply separate the walls of hydro bag and let gravity to do its buiness.
To hang up upside down use for example theRachet's Camelback Hook, or cord.
https://www.printables.com/model/108501-camelbak-drying-rack-and-hook/files