What is it?

A robust protective case for your iPhone which contains an integrated power generating crank arm.

To accommodate hours of usage smartphones used to be very bulky and that was accepted as part of the experience. Then came the trend for increasingly slimline gadgets that could easily fit into a pocket, but with that came the downside of a reduced battery life. The introduction of the portable power bank tried for a happy-medium, but couldn't resolve the issue of needing additional space in a pocket or bag for this often heavy secondary device.

This is where the AMPware case ushers in a new era of power creation. Based on the slick Trevor Baylis wind-up radio, the case generates power by rotating the built-in crank arm.

Good Points?

The case is well designed and sturdy enough to withstand most violent impacts. The crank arm tucks away neatly behind when not in use and also doubles as a useful stand for watching videos. Operating the crank for five minutes generates enough juice to power the smartphone for up to an hour. The case costs far less than a quality power bank and you don't need to worry about remembering to regularly recharging – the power is all in the arm.

Bad points?

Trotting out the old "sorry, my battery died" excuse when trying to dodge unwanted phone calls will no longer wash.

Best for ...

Those in emergency situations or the likes of campers, festival goers and hikers who don't have access to an electrical socket.

Avoid if ...

Your mobile phone is not an iPhone 6 or later.

Score: 9/10

AMPware Power Generating iPhone Case, £69.99 (getampware.com)