Where can I get a replacement pin pad for my smart lock ?

It looks like both the indoor unit and the PIN pad have their own batteries. How do I replace the batteries on the PIN pad and what type of batteries do they use?  How long do the batteries last on the indoor unit as well as the PIN pad on the outside?

It looks like both the indoor unit and the PIN pad have their own batteries. How do I replace the batteries on the PIN pad and what type of batteries do they use?  How long do the batteries last on the indoor unit as well as the PIN pad on the outside?