According to Apple, the Apple Watch has an 18-hour 'all-day' battery life. If that sounds too short to you, you may want to consider the Reserve Strap, a watch band with embedded lithium-polymer cells capable of charging the Apple Watch through its hidden accessory port.
Made with 'specialised thermoset elastomer silicone' and is 'as resistant to water as Apple Watch', the Reserve Strap is available for both 38mm and 42mm Apple Watches, and fits wrists 130 to 210mm in circumference. Charging (of both Watch and strap) is done via a micro-USB port on the strap, and there's an LED on it that indicates how much charge is left. According to its maker, the Reserve Strap adds 30 hours of additional battery life to the Apple Watch.
Alas, while design and technical specifications have been finalized, the Reserve Strap (available in white, gray, and black colors) is only shipping in November, which is still quite some time away. Also, it costs US$249.99 (S$338) a pop, more than half the price of an Apple Watch Sport. If these aren't enough to deter you, you can pre-order one now on Reserve Strap's official website.
Source: Reserve Strap.
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