Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Batteries!

I bought these as my annual smoke detector replacements. The previous set of the same batteries caused no problems...all lasted for a year with no issue. They are used as battery back-up for a hard-wired system, so they rarely get used. In fact, I don't believe we have experienced a power outage since they have been installed. Regardless, they seem to work and came at a great price.