Abstract: The present development is a liner unit comprising a light-weight polymeric material that becomes cold when exposed to water, which can be used to line a soft-crown cap, such as a baseball cap. The liner is sized to fit snuggly within the cap, and may be reversibly attached to the interfacing of the cap. Alternatively, the liner may comprise a magnet, sized and oriented on the liner so as to allow the magnet to engage with the underside of a button secured to the cap.

Abstract: A camera flash socket, adapted to releasably retain the base of a flash unit, has a plurality of resilient fingers for engaging retaining surfaces in the base of the flash unit, a projecting portion for preventing improper insertion of the base of a flash unit in the socket and a plurality of electrical connectors. In a preferred embodiment, the flash socket includes three connectors in the form of spring-biased contacts and further includes two pairs of opposed resilient fingers, the fingers being positioned to retain the base of the flash unit in the socket when the base is presented in a proper orientation with respect to the socket.