Donald is correct, the bridge circuit in the meter of the SpotMatic is independent of the voltage and any approximately 1.5 volt cell will suffice. I tried the Zn/air cells with success but they constantly discharge as soon as the seal is removed. So it runs down whether you use the meter or not. They only lasted a month for me. I use a Ag/Zn now and check it against my spot meter regularly. It is a great camera - I even found a fa/2.8 Vivider 80-200 zoom. Never seen one before or after. According to my sources, that lens was made by a very reputable Japanese maker. Good luck - I'm sure you will enjoy the operation and the results.