The Acapella® device uses a counterweighted plug and magnet to create vibrations or oscillations of the flow of air in the lungs. It can be used in any position. The Acapella® has a circular dial at the back which changes the position of the magnet to create variable PEP resistances. The Acapella® Duet has a built-in nebulising unit. The Acapella® Choice and Acapella® Duet can be dismantled for thorough cleaning.