The inductive output tube (IOT) or klystrode is a variety of high frequency transmitting linear-beam vacuum tube, similar to a klystron, which evolved in the 1980s to meet increasing efficiency requirements for high-power RF amplifiers. The primary commercial use of IOTs is in UHF television transmitters, where they have mostly replaced klystrons because of their higher efficiencies (35% to 40%) and smaller size. IOTs are also used in particle accelerators. They are capable of producing power output up to about 30 kW continuous and 7 MW pulsed and gains of 20–23 dB at frequencies up to about a gigahertz.