Panasonic hearing aid batteries, or zinc air batteries, do not contain active materials in their positive electrode. This type of battery reacts with air - so it’s important to remove the tag before inserting the battery into your device. Be sure to let the battery breathe for a few minutes before inserting it into your device.
The initial voltage before peeling off the seal is 1.0 to 1.2V while nominal voltage is 1.4V. However, the battery’s voltage will increase gradually once the seal is removed. Just for your reference, nominal voltage stated in JIS standard is max 1.68V and minimum 1.3V.
Since no space is required for a positive electrode, more active material can be used for the negative electrode. Hence, the battery can be used longer.