Feature:The ideal solution for many cameras such as the Olympus OM1, Rollei 35, Yashica 124G, etc that used the original PX625 (1.35V) battery. (But will not fit Leica M5)Today's equivalent to the PX625 battery is the "PX625U". It is the same size and shape, but the voltage is 1.55v - which means that the battery will give an "over-voltage" and would give incorrect meter readings.One of the solutions is to buy a Weincell PX625 Battery, which at around 6.99 can make running your camera a bit expensive (as zinc air batteries only last a few months once they are activated)So is there another solution Yes - fit this adapter (which is the same shape as the PX625 battery) into the battery terminal of your camera and power it using a "Zinc Air 1.4v battery "- the good news is the 1.4v Zinc air battery (which is shaped like a standard LR44 battery) can be bought for around 50p - so it is a great saving if you use your cameras often. The zinc air battery are known as 675 battery (aka: hearing aid batteries)The adapter is precision madePlease note: the listing is just for the adapter only - the "1.4v zinc air batteries" can be found online from a number of sources(Image shows original PX625 battery against adapter and Yashica 124G - both of which are not included)Q: Will this convert the voltage of a battery A: No - the adapter will not convert a voltage - it only converts the physical size of the batteryQ: Is there an adapter made that converted voltage A: Yes, there is an adapter made with a small micro chip - however, they are not too reliable - they work fine at the beginning, but after a few uses they start to give intermittent problems with the voltage. Our adapter has no chip, so it is much more reliable - and still gives the correct reading (When using zinc air battery).Q: So what battery do I need A: You will require a Zinc Air 1.4v battery - which is known as a 675 (often referred as a hearing aid battery). They cost around 50pName:Battery Converter AdapterPacking List: 1xBattery Converter Adapter( Battery is not included)