Batteroo Boost Battery Life Extender Review @ Bigbruin.com
 

Last year I went to a trade show and spoke with the inventor of Batteroo. The presentation almost sounded too good to be true, citing claims that a recent study showed that most discarded batteries had up to 80% of the original energy still stored inside. Of course their device can solve this problem by maximizing the use of all of your alkaline batteries. Currently the product is for sale through Indiegogo and directly from their website, where a 4-pack of AA Batteroo sleeves is $10 plus shipping.

https://bigbruin.com/content/batteroo-boost_1