9V Battery for Smoke Detectors, Carbon Zinc 6F22 PP3 EN22 Batteries, Ultra Long-Lasting (4 Pack)

I bought these batteries as replacements for all the smoke detectors in our home. I believe we have always had less trouble and frustration when we replace them all at once as soon as the first one starts beeping instead of replacing them on a set schedule or just one at a time. I like to write the installation date on each battery with a Sharpie pen so I can see how long they have lasted. Since I use 9V batteries in different applications, I test the batteries that I just replaced and keep the best ones for my volt meter, stud detector, and other less critical devices. That being said, the initial quality and value of these batteries seems to be very good, but I plan to update this review as soon as they need replacement.