Samsung slimmed the Ultra 2 by 12 percent while jamming in an 800mAh battery, 35 percent bigger than the first version's 590mAh. It now works as a diving computer, tracking depth to 40 meters through a partnership with scuba-gear maker Mares. Snorkeling and diving down to 100 meters are on the menu. At $700 with an August 7 release, it's the strongest Android watch mostly because the competition is thin.