 It was manufactured in the U.K. by the MOV (Marconi-Osram Valve) subsidiary of G.E.C, also labelled as IEC/Mullard, and, in the U.S., Genelex "Gold Lion".As of 2018, KT88 valves are produced by Shuguang (China), JJ Electronic (Slovakia), Svetlana (Russia), and New Sensor Corporation (Russia).NOS examples in good condition are extremely rare.