This is an adapter for converting to MR-9 batteries, a type no longer sold, for use in film cameras. Retail price at Kanto Camera Service: 3,630 yen Purchased new and used only for two rolls of film in one camera. 【Typical Compatible Models】 Basically usable with cameras that require MR-9 batteries, such as the OLYMPUS OM-1, Nikomat, and others. It converts silver oxide batteries SR43 to the external shape of mercury batteries MR-9, and also converts the 1.55V voltage of SR43 to approximately 1.35V, allowing you to use your camera with a voltage closer to that of the mercury battery MR-9. ◎ The batteries in the last image were only used in the camera for a few days, and still have plenty of charge remaining, so they will be included as a bonus.