Details
New old stock octal twin triode with graphite anodes. Various brands. The 6336A and 6336B have heater currents raised to 5A from the 4.75A of the 6336A. They also have additional vibration specifications. The "A" meets military specification MIL-E-1/704C. The "B" meets military specification MIL-E-1/1478E, which requires extra fatigue testing as well as having a looser vibration test specification.
NSN/FSN = 5960005427216, 5960006080232, 5960008820180, 5960009178493
Tektronix Number = 154-0423-00