Small, handy and very safe: The Rapid1G Taillight from CatEye. It is very practical and can be easily mounted on the seat post with its flexible bracket. The rechargeable battery saves you the hassle of buying regular batteries - it can easily be recharged via USB and lasts up to 4 hours. The Rapid1G taillight is always there and a real help on the road.
Note: The taillight is permitted for all bicycles in accordance with German road traffic regulations.