Alternatives to CSB - no!
Over the years, we have tried such battery brands as: Delta, Sven, Ippon, Ginzzu, they do not work for more than 1-2 years and the indicated capacity is often not true, although there are long-livers in the reviews, but this is more an exception than a rule
Trend based on tests, after a year and a half of operation in the APC UPS, the capacity is reduced by 0.5~0.7Ah
IMHOSee full review