Cochlear implant systems are used in diverse environments and should function during work, exercise and play as people go about their daily lives. This is a demanding requirement, with exposure to liquid and other contaminant ingress from many sources. For reliability, it is desirable that the speech processor withstands these exposures. This design challenge has been addressed in the Nucleus(R) Freedom(TM) speech processor. The Nucleus Freedom speech processor complies with International Standard IEC 60529, as independently certified. Tests include spraying the processor with water followed by immediate verification of functionality including microphone response, radio frequency link and processor controls. The processor has met level IP44 of the Standard.