I bought these for a semi-annual smoke detector battery change out. I like the way each battery is individually shrink wrapped because of the short problem while storing the batteries. I also installed one in my carbon monoxide alert system and it kept 'chirping.' I checked the voltage of the new battery and it was only 4.7 volts D.C. I also had a second dead battery, so 2 of the 8 were duds. I didn't return them because of the hassle. I will not buy these again because the quality control is NOT good.