GoPro camera makes Californian surfer CEO a billionaire
The tiny high definition camera called the GoPro has made its company's founder and chief executive a multi-billionaire.
Nick Woodman's company has sold 10 million of the devices since 2009.
Rory Cellan-Jones met Mr Woodman at the BBC in London to talk about what made GoPro a success in a world where the smartphone is king.