Triodes and a few tetrodes were made. However, this was at the very limit of the power-handling NT100 tetrodes. In technical terms, JJ produces triodes, beam tetrodes and power pentodes. But in older transmitters tetrodes or klystrons are also utilized. This tube saw little use as standard triode and tetrodes could function adequately as dynatrons. In addition, there were some examples of beam tetrodes designed to work in-place of pentodes. The 4CX250B tetrodes used a grounded plate (anode) due to forced aircooling requirements. Post-Williamson, most commercial amplifiers have used tetrodes in the "ultra-linear" configuration.