Artemis's phone vibrated gently. Usually Artemis deplored the kind of person who kept their phone on during a performance, but this phone was special and he never turned it off. It was the fairy communicator given to him by Holly Short, plus a few modifications and add-ons made by Artemis himself.
The phone was the size and shape of a two-euro coin, with a pulsing red crystal at its centre. This was a fairy omni-sensor, which could interface with any communications system, including the human body. The phone was disguised as a rather ostentatious ring on Artemis's middle finger.
Artemis twisted the ring so that the phone sat on his palm, then closed his middle fingers, extending his thumb and little finger. The sensor would decode vibrations in his little finger and send them as voice patterns. It would also use the bones in his hand to transmit the caller's voice to the tip of his thumb.
Artemis looked for all the world like a young boy talking on an imaginary phone.
'Holly?' he said.

The Lost Colony, Chapter 4