the fenix lights work great as bike lights, I still prefer to use an additional light on the helmet.. I use the p2d, it is very small and works with 1-cr123a batttery.. If you use in high mode you will get 3 hours of burn time.. A helmet light is a must in terms of being seen or seeing through corners since you can direct the light better.. I use the twofish bikeblock.. This is the holder that runs in parallel fashion and works great as a helmet mount..

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