I bought these batteries for a Garmin chest-strap Heart Rate Monitor. Garmin says to expect about 6 months or more per CR2032 battery. So far, I've experienced some weakness in trying to power a chest-strap Garmin heart-rate monitor with these batteries. That is, my heart-rate graph gets erratic after I've used a battery for just a few hours. I'm not sure if the problem is the batteries or the strap. I have a new strap on order, so I will update this review once I've inserted a battery into a brand-new chest strap. I have purchased these batteries in the past with satisfaction. What I love is having a pack of these affordable batteries in my gym bag so that I need not worry about not having a functioning fitness watch.