Phonak Invisity Flex IEM Receiver Earpiece Prompter by Phonak is the smallest in-ear RF receiver in the world and the perfect choice for presenters and performers who require crystal clear audio prompts. Invisity is completely wireless, sits invisibly inside the ear canal, and weighs just 1.5g. It offers total freedom of movement and is ergonomically designed for day-long wearer comfort. Today invisity is used and trusted by broadcasters and filmmakers worldwide. Always use Invisity with Phonak A10 batteries. Invisity Flex Single channel (7 MHz range), programmable via the optional invisity programming unit (IPU) or through a Phonak dealer.