Phonak CeruShield Disk is the new wax system from Phonak designed as an easy to use dispenser wheel. The CeruShield Disk consists of 8 new CeruShield filters and 8 positions for easy disposal of used wax filters. CeruShield filters protects the receiver from wax related problems and offers longer wearing time between filter changes. CeruShield filters have been designed specifically to be used with Phonak's SDS 4.0 receivers. Please note that Phonak CeruShield is only compatible with Phonak SDS 4.0 Receivers (used on Phonak Marvel hearing aids) and is NOT compatible with older receivers.