Stop in for a cup of coffee

So strange story. I have a auto darkening welding helmet. Well, since new it only worked some of the time. About 50/50. So I thought the battery was low. But no battery low indicator was lite. Remember it WORKED about half the time..... Well, went to replace the battery, and....there was NO battery in it!!!!!!!!!!!!!!!!!!!! WTF??? How did it work at all???????? Put in battery and it works great now...:realcrazy::lol: