Printed in silver ink on top of the glass envelope.
overall: 3 1/8 in x 1 1/8 in x 1 1/8 in
There are six tubes catalogued in this record. This is a power pentode in a glass envelope with an eight-pin loctal base. This is a spare tube for Bus Driver Arithmetic Rack S/N 10. One of the tubes has a red circle drawn around the perimeter at the top of the tube and "WAD33" handwritten around the envelope near the base in red nail polish.