I do a bit of off-road running in the dusk or dark at this time of year and have been using a Petzl Myo for the last two years - it's a great light but I have just bought a Rayovac Highbeam on ebay (as a spare, for £18) and it blows it away! I don't know whether it is of the same build quality and I don't really know how long the batteries last (I ran for half an hour and didn't notice any deterioration). The beam is rather more narrow but it is fine for running. Has anyone else used one of these?