

Reserve Strap
The Reserve Strap is the first battery band to be made available for the Apple Watch and addresses key concerns with battery life that a number of users have raised regarding the device, namely its inability to make it through more than a day on a single charge.
The Reserve Strap is in full compliance with Apple’s Band Design Guidelines and won’t violate your AppleCare warranty. The Reserve Strap makes use of the Apple Watch’s hidden diagnostic port to enable seamless charging of both watch and band, though unfortunately in order to charge both at the same time you have to do so through the Micro USB port on the band rather than using the Watch’s magnetic charger.
For what it does, the Reserve Strap definitely seems like a huge chunk of change, but for significantly extending the battery life of a device that can cost upwards of $10,000, it may be worth the premium for some users.