The Eton BoostTurbine back-up battery charges most mobile devices via a USB port. Its special feature is, however, hidden on its reverse side. There you will find a hand-operated winding mechanism, which can be turned to produce energy without using mains electricity. The energy thus produced is sufficient to power a mobile phone long enough to make a short phone call, making BoostTurbine a useful device in an emergency. The battery is made using aluminium die casting, polycarbonate and rubber and stands out thanks to its perfect size.