1Pc PX640 Battery Adapter for Film Camera Exposure Meter Mercury Electro 3YUAA | eBay
PX640 Battery Converter Adapter for Film Camera i.e. Olympus 35EC, Electro | eBay
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Camera Battery Adapter
MR-52 and MR-44 Adapter combination. Replacement for PX640, NR52, H-N or MR52 discontinued Mercury cells.