Maintains the water level of your aquarium for a few days.
I designed this piece to screw onto a 660ml "cola" bottle. It must be fitted on the glass of the tank with the two holes touching the level. For a few days of absence from home the fish will be fine.
You need to add a few turns of Teflon plumbing tape to the thread of the bottle.
The author marked this model as their own original creation.