This is a battery adapter to let you put a 675 hearing aid battery in a PX625 meter camera. For further reading on the topic, see: https://www.flickr
MR-9: Ideal PX13 and PX625 replacement.Features MR-9, a battery-adapter with built-in circuitry to reduce the S76 silver oxide battery voltage to that of the mercury battery. Replacement for PX13 and PX625 mercury batteries; Efficiency of MR-9; Retail costs....