Concord Keystone ( has introduced the US$69.99 Keystone ECO holster with a built in rechargeable battery that provides back-up power and automatically recharges iPhone 3GS and iPhone 3G.

Available in black or white matte finish, the hard case design provides full front and back protection for the Apple smartphone. The Keystone ECO holster uses a mechanical spring sliding action that enables users to slide the case open and remove the iPhone from the charging case, leaving the auxiliary battery in the holster, and lessening the battery bulk when iPhone is in use.

The rechargeable 1300 mAh Lithium-Polymer battery is housed in a slim polycarbonate case that clips to belts, waistbands, handbags, or briefcases. To use the Keystone ECO holster, users slide iPhone 3GS or iPhone 3G into the holster and the phone automatically begins charging the battery, providing a full charge in under three hours.

The holster or the holster/iPhone combination can be charged by connecting it to a computer through a USB cable, or by using a wall adapter with USB port. While connected to a USB power source, a battery indicator light on the bottom of the holster signals the battery charge status by changing color (red, yellow, and green) corresponding to the level of charge. Users can manually check the battery charge status by pressing the battery check button at the base of the holster anytime.