Vacuum tube type SR1407
||Printed in silver ink on top of the glass envelope.
||O 1D3 V22-2
||Handwritten in green ink vertically on glass envelope.
overall: 3 1/8 in x 1 1/4 in x 1 1/4 in
This is a pentode in a glass envelope with a loctal base. This is a spare tube for Register Driver S/N 6.