The Phonak 4.0 Hearing Aid Domes offer various sizes to customise your hearing aids to make them as comfortable as possible. They are compatible with Marvel, Paradise & Lumity Hearing Aids and are available in 4 different styles with 3 sizing options. The Open style is rounded and allows natural sound to pass through, ideal for compensating high frequencies that you may struggle to hear. The Vented style is for moderate hearing loss and are bud shaped with small openings for ventilation. The Power style domes feature double skirts which create a stronger seal, making them better suited to people with moderate to severe hearing loss. Finally, the Cap style is a simple cap on the end of the receiver which is most suited to people with small or narrow ear canals.