The 1500T is a 1500 watt triode with a mu of 24 and a maximum frequency of 40 MHz. Made by EIMAC. Length = 17.00" Diameter = 7.13" Max voltage = 8000 Max current = 1.25 amps Fil voltage = 7.5 Fil current = 22 to 25 amps Data sheet: GOTO INDEX