MR-9 batteries are used for vintage film cameras.
However, MR-9 batteries are can't get at now.
This is a solution for the discontinued MR-9 mercury battery.
Use of SR43W Silver Oxide battery (1.55 V) to convert voltage to MR-9 Mercury battery (1.3V).
The diameter of the anode is slightly larger than MR-9.
Therefore, there may be cameras that can not be used.
The function of the adapter was confirmed with the following camera.
ABS Layer:0.1mm Nozzle:0.4mm
Tin-plated copper wire with a diameter of 0.5 mm was used for wiring.
The diode is SB 1003 M 3.
Diode was small and it was difficult to solder.