Jackery has introduced the Jewel, claimed to be the first-ever Apple-certified Lightning-to-USB cable with a built-in battery for iPhone, iPad, and iPod models.
The 3.2-foot cable features an integrated 450mAh battery that can, for example, fast charge an iPhone 6s up to 26% or an iPhone 6s Plus up to 16%. Like any other Lightning cable, the Jewel can provide a 1 amp charge from any USB power outlet or transfer data from the iPhone, iPad, or iPod to a connected Mac or PC.
The cable also has a built-in LED charging indicator:
A built-in LED on the battery and charger case gives users information on battery levels. In charging mode, an LED flashes and illuminates in red, green or blue to indicate levels, and users can also push the cable's power button to check battery levels. The LED also indicates levels in recharging mode and will continue flashing until the battery is fully charged.
Update: As several readers have pointed out, Native Union also offers an MFi-certified JUMP Cable with integrated 800 mAh battery for $50.