Dive Rite B'Air Battery Life

Someone local to me is selling a used Dive Rite B'Air wrist computer for a pretty good price. My issue, since the computer is used, is the battery life. I don't want to find out I got this thing for a good deal only to find out it is just 1% from not allowing the computer to enter dive mode. Then I have to send it off for a battery replacement to an authorized dealer.


Prior to showing a battery alarm or alert is there a way of checking the battery life as a percentage or does the size of the battery shrink as its life is depleted?

Any info would be greatly appreciated.

Battery life is crazy for sure. I own one since 2000 and i have change battery only once 2008 and used on more then 1000 dives