I was chatting to someone armed with a pair of bocks, on the train home this evening. He said that his pair cost around £140, and that he was able to spring 'above his weight' which means that he can bounce higher - but only with a lot of effort. This gent serves in the Royal Air Force, and had just returned from Kandahar in Afghanistan. He had taken his bocks with him on his last mission, and actually wore them at 33000 feet! They came in handy when he was rested in a six-star hotel in Oman on his way back. Instead of bouncing off the walls with boredom, he was able to bounce around the complex!