Cerumex waxguard: The cerumen filter system is used to stop ear wax entering in-ear receivers such as invisity. Phonak invisity is the smallest in-ear radio receiver in the world. Comfortable to wear and offering market-leading sound quality, this invisible earpiece allows broadcast and stage teams to discreetly prompt any presenter or performer, in turn providing these professionals with a valuable safety net and ensuring that broadcasts and performances always run smoothly.