IMPORTANT: If you have a new-style tag (Tag ID 10,000 and above) You will need to turn your tag on after replacing the battery by pressing the white button for 5 seconds.
Yes and yes! Huan tags are designed to last, and the battery is fully replaceable.
To replace the battery, take the plastic casing out of the silicon sleeve, and pop it open. You will see the battery holder which contains the battery itself - simply slide it out and replace it with a brand new battery. Carefully place the tag back inside the case, and align the top and bottom parts until you can press them shut.
Make sure you slide the new battery in using the same direction as the previous battery to preserve polarity and ensure correct operation.
NOTE: Huan Tags use CR2032 or CR2032H coin cell batteries.