I just want to second this recommendation. I bought these based on recommendations from another forum in spite of my reservations about buying something suspiciously cheap from China, but have been absolutely wowed. I get 2+ hours runtime on the low setting, the light doesn't fade as the battery runs low, and the lowest setting is extremely bright - enough so that the only time I've needed the mid or highest settings when descending at 30mph or faster without ambient light or streetlights. Only downsides are that the beam pattern could be better (but really, the light is so powerful it doesn't make much difference) and you have to be somewhat creative with the velcro strap on the battery holder if you're attaching it to an older bike with small diameter tubing.