Bests & Worsts Reviews from Amazon

***UPDATED 4/29/2018 -- shortly after I wrote this review, I tossed out the entire box. So disgusted, I didn't even want to hassle with sending back for a refund. TRASH! ** This weekend I received the batteries and a First Alert carbon monoxide alarm. I bought the 9v for this purpose - and to use in the smoke detectors. When I managed to wedge in the slot, the connectors did not fit the alert. I turned it upside down thinking I had installed incorrectly. No. I was surprised that I had to forcibly push it into the slot, because of the extra width compared to standard 9v batteries. After no more than 20 seconds of this, I took it out and it was warm, which I thought was odd. In the next minute, I could actually smell the chemicals, and touched it again. It was HOT! Too hot to hold and, truthfully, I was sure it was building to explode. I put a cup over it until it cooled off. I've never had this kind of a reaction with a battery. Ever. Maybe I just had a bad batch, but once is enough for me. I then inserted the Eveready which came with the detector. Problem solved. These are being returned. I am not a name-brand snob. Quite happy with the Amazon basics AA & AAA batteries. **Before I clicked 'submit', I checked the Eveready and tested the alarm. My furnace died the other day (which is why I wanted the CM alert) and it is 59 degrees in my house. The battery was just as cold to the touch. Win.