it's a knee generator developing 5 watts of power, and at the moment is at the design stage......as you can clearly see..... because you couldn't wear THAT under your jeans, apparently it is only good for charging mobile phones at the moment and does slow the walker down, and the designers say it has applications for hill walkers etc
you have to ask the question why would a well prepared hill walker go out in the wilds with a mobile phone where the battery was flat, but they had the forethought to pack this metal brick in their backpack ?
Surely it would be better to make sure your phone was charged before you left the house ? plus I can't see walkers walking around with one of these strapped to their knees ruining their very expensive all weather walking trousers, and the last thing you want on a trip up Snowdon is this mechanical leech sapping your very last energy reserves to top your phone up !!! mind you if you are lying injured in some ditch and your mobile phone is flat I can't think of a better device to use to summon help.....mind you, you would need to do 500 knee jerks before you got a usable signal ;¬)