🔋 Durable Duracell Procell 9V Batteries - Pack of 12, with Varying Packaging Options Review

I bought these on the eve of the annual battery change in smoke detectors. I've never heard of Procell and I usually buy large batteries from Costco. I need 10 and Costco changed their packaging to 8 by increasing the price so I looked around and found this. Research on battery websites shows they are the same as the leading copper consumers, only packaged in bulk. Some research suggests that prosells have a slightly higher initial fee. I measured 9.7 volts on them and 9.4 on a fresh copper tip

The Duracell Procell has the same capacity as the Duracell 9V battery, so don't let the name fool you. Procell represents an industrial or professional force, but actually it is not. The only difference is the lack of retail packaging and how they mark the product (appearance). Battery life (without use) depends on the material it is made of and depends on the storage conditions. Ultra (AA/AAA) = 10 years. CopperTop (AA/AAA/C/D) = 10 years. Copper tip (9v) = 5 years. Lithium coin = 10 years…

I bought my first box of these batteries in July 2015 and am very happy with them. All 12 were fully charged and the 'use by' date was March 2019 with a shelf life of just under 4 years. The box and batteries were marked "Assembled in USA", although this text implies that the components were manufactured outside of the USA. Plastic protective caps had holes at the top, making them easy to check with a voltmeter. The few I have left from this purchase are still charged and usable. I would rate…