The recording electrodes can be carried by a skull cap, and nothing has to penetrate the skin.

ECONOMIST: Bionics (I)

On January 7th, he dutifully donned a black skull-cap for a reverential photo-opportunity with Rabbi Ovadia Yosef, spiritual leader of the powerful Shas party.

ECONOMIST: Israel

Only later did his measurements show that the skull-cap was from a new transitional species, pithecanthropus erectus, the upright ape-like man.

ECONOMIST: How man has learned, through history, about his habitat

Mullah Mairbek Yusupov is a small bearded man dressed in a green surgeon-style top and skull-cap.

BBC: 'Exorcisms' performed on Chechen stolen brides

The CheckLight itself is composed of two parts: a sensor device built by mc10 and skull-cap made by Reebok.

ENGADGET

The CheckLight itself is comprised of two parts: a sensor device built by mc10 and skull-cap made by Reebok.

ENGADGET

And, as in any convertible, it will make you think twice about wearing a baseball cap, lest it gets whipped off your skull at speed.

FORBES: Overview