The unit comprises a pocket-sized storage and viewing system, linked to a camera worn at the side of the head with the aid of a strap. It is described as an Archos Gen 5 Helmet Camera, and is connected to an Archos Gen 5 Portable Media Player. Together, the two units cost less than $500.
The press article about door supervisors and headcams can be found at:
http://www.kent-online.co.uk/kol08/article/default.asp?article_id=48491