The GU-74b or ГУ-74Б is a 600 watt, forced air-cooled, tetrode with full power output to 250 MHz. Made in Russia. Length = 3.38" Diameter = 2.75" Max voltage = 2000 Max current = .75 amp Fil voltage = 12.6 Fil current = 3.3 to 3.9 amps GOTO INDEX