Details
New old stock octal full wave rectifier. Tubular T9 bulb. Various brands. Essentially an octal type 80 and a 5Y4 with a different pinout.
NSN/FSN = 5960001077583, 5960005489735, 5960005672380, 5960006922690, 5960008458407, 5960008796563
Signal Corps Number = VT-197A
HP/Agilent Number = 1930-0010
Tektronix Number = 154-0009-00