This tube, IN-5A-1, is very special: it has the same small shape of the IN-2 tube with a different socket and is the twin of the IN-5B-1 tube which has only three symbols as this model. It has an ‘X’, a ‘Z’ and an ‘x’.
|symbols||-||Z, X, x|
|dimensions||mm||⌀ 8 x 40|
|socket or alternative||-||7 pin miniature socket|