and you're on top of it. Grateful for the service in any event.
(Just thought, maybe.. it was a '1' in a box? which might be changed to a 2 or 3.)

PS - I'm on 15th? 16th? year on an early APC UPS (too lazy to schlep it out for model #) -- sold back when only the cognoscenti ordered such stuff.
I bought original-brand replacement batteries when these approached about a 3 min capacity, on the basis that this set of e- is bloody-well past infant mortality,
and the battery supplier wasn't too shabby either (at ~ 12 years, say?)

Love It - on those rare occasions when it makes sense to keep an elderly but decent design working forever.