A valve (vacuum tube) is an electronic switch that controls the flow of electrical current. Valves are a basic electronic component used for circuitry and memory in First Generation computers. The valve pictured is a 'KT88', manufactured by the General Electric Company (GEC), a major multi-industry British business which operated in the electronics, communications and engineering sectors. During the 1980's GEC was Britain's largest private employer with more than 250,000 employees. First introduced in 1956, the KT88 valve was purposefully developed for use in high quality audio equipment; for this reason it is still purchased by hi-fi enthusiasts today!