Printed in barely legible silver ink on top of the glass envelope.
overall: 2 7/8 in x 1 1/8 in x 1 1/8 in
There are 12 tubes covered by this record. This is a power pentode vacuum tube with a loctal base. This is a spare tube for Bus driver arithmetic rack, S/N 10. There are no complete legible markings on these tubes.