The 4CX250B (7203) is a 250 watt, forced air cooled, power tetrode with a full rating frequency of 500 MHz. The same tube with a 26.5 volt filament is the 4CX250F (7204). Other varients include the 4CX250BC (8957) with a 6 volt at 2.4 amp filament designed for longer life and the 4CX250R (7580W) with a 6 volt at 2.6 amp filament for high shock and vibration environments. Mechanical samples for these tubes were made for designers to use. Many of these tubes were good.
Length = 2.47" Diameter = 1.64"
Max voltage = 2000
Max current = 250 ma
Fil voltage = 6
Fil current = 2.6 amps