Yes, the batteries' weight does change during usage.

No. Do not use batteries in water or in vacuum conditions - this will cause them to rust and short-circuit.

When inserting a battery, make sure you do the following: insert it the correct way, with plus and minus poles touching the right terminals; use the right coin battery size; avoid dirt or any other substances obstructing proper contact; carefully insert it, not putting stress on it as you’re closing up the holder. Makes sure it makes contact with the terminals.

The ideal temperature for our primary batteries is between 5°C up to 45°C. 

You can, but they’ll perform best in medium- to high-drain devices.

Never apply heat to batteries. Keep them away from any heat sources like heaters, candles, stoves and fires. Exposing them to too much heat could cause them to tear, leak or even explode.

All batteries, including Panasonic hearing aid batteries, can and should be recycled.

Battery performance greatly depends on the device and on the conditions.

Please seek medical attention immediately. While serious accidents are relatively uncommon, swallowing a coin battery may still cause burns or breathing difficulties.

Panasonic hearing aid batteries contain zinc, which reacts with air. They do not contain lithium.