The display on this looks like it's nixie tubes. Looks like 24VAC plus 450 VDC power required.https://www.ebay.com/itm/Thornton-Associates-Inc-DEC-102-Decade-Counter-Decimal-Digits-Laboratory-Unit/232161267621?hash=item360de3cfa5:g:-MQAAOSw-0xYQHPq