Scuba divers must master neutral buoyancy through breathing so that they do not get into emergency situations in the sea or cause damage, e.g. to coral reefs, through their lack of expertise. Blow-yancy is a virtual reality device which helps to train the ability to control position underwater through breathing. It consists of a mask with a controller, a built-in breathing sensor and buoyancy control. The nose-covering mask is designed in such a way that, together with an accompanying app, it gives the impression of wearing a real scuba mask under water.