Mercury batteries are commonly found on cameras and exposure meters produced in the 60s to 80s. Canon F-1, Minolta SRT-101, Leica M5, and Yashica 124G are some famous cameras that use mercury cells. Today, most countries have banned the production of mercury cells due to environmental concerns. Thus, a suitable replacement battery is required to bring them back to life.
Zinc-air battery is a perfect substitute for mercury batteries. As shown in the diagram, both the zinc-air and mercury batteries have a similar discharge curve and range of output voltage. Therefore, you can achieve accurate exposure results with this direct replacement.
The labelled voltage (1.45V / 1.4V) on the packaging is the peak value measured by the manufacturers. After removing the seal, please wait for 30 minutes before use. It allows the battery to stabilize the output voltage (1.38v to 1.32v). Each zinc-air cell lasts around 1 to 2 months.
Remark: Do not use alkaline or silver-oxide batteries on mercury cell-powered devices. Otherwise, it might damage the device permanently. Please recycle batteries after use.