Equalises the pressure in the middle ear. Earpain / Freediving

Ear pain.

You put a balloon over the flat side which your child blows up through their nose. The act of blowing up the balloon helps to open up the Eustachian tube, making it easier for fluid to drain from the middle ear. The balloon equalises the pressure to relieve the symptoms in the middle ear.
This also helps for people who experience ear pain during plane flights.

Freediving.

With this you can improve your ''mouthfill'' equalizing technique.