1.ISO9001:2008&CE 2.glass triode tube 3.anodes cooled by nature. 4.audio power transistors FU-501is glass triodes,audio power transistors ,with their anodes cooled by air, and their maximum anode dissipation powers at 450W; when at a frequency not higher than 30MHz, their output powers may attain to 1500W. They are mainly applied in industrial high-frequency heating equipments for oscillations or ...