Panasonic will begin shipping its long-lasting EVOLTA AA and AAA batteries to the US next month. According to the company, the AA cells -- like their AAA counterparts, $5 for a four-pack or $9 for an eight-pack -- have been recognized by the Guinness Book of World Records as the longest lasting in their class over the broadest range of devices, based on ANSI- and EIC-compliant testing. Panasonic's own tests reportedly show that an EVOLTA-powered digital camera took 30% more shots than one equipped with the company's Alkaline Plus batteries (but not its more recent OxyRide models, it should be noted), while similar setups showed a 14-hour gain for an FM radio and 8.7-mile advantage for an RC car. The batteries get their longevity through a combination of innovative chemicals which create more powerful reactions, the company reports, along with a refined manufacturing process that packs "active materials more evenly and densely."