You've been able to get third-party battery cases for the iPhone for a long time now, but Apple has finally decided to step into the battery case game itself. It has launched its own slim case for iPhone 6S and iPhone 6 smartphones.

The Smart Battery Case looks similar to the company's existing range of iPhone cases, but has a built-in battery element that promises to increase your talk time up to 25 hours or give you a further 18 hours of surfing on a 4G connection. 

The case, which slips over the iPhone rather than bolt around it, will come in two colours - charcoal or white. But those who prefer a slim device will need to be aware that the additional battery life comes with a caveat, it does add some extra length and thickness to the iPhone.

Apple claims its battery case is better than others because users will be able to swipe down in the notifications centre to see the battery levels for the iPhone and Smart Battery rather than relying on a button on the case itself.

When you plug in the case to charge, there’s also a battery indicator on the lock screen that tells you how much charge the iPhone battery and the external battery have.

Unlike most battery cases available today, this one is charged via Apple's standard Lightning cable.

The new iPhone battery case works with the iPhone 6 and iPhone 6S and costs £79.99. There is no word whether the company will be releasing a version for the iPhone 6 Plus or 6S Plus, or customers that still use the iPhone 5, 5S and older devices.