Rear light for very original bike with these two lazer that illuminate a safe zone around your bike. Fire with 8 red LEDs, has three operating modes: random flash, quick flash and fixed lights. Most of the product: It is rechargeable by USB and charger supplied. Its service life is more than enough for a ride one day. For longer trips, an external battery and the cable is specific voila! The document is brief and English but there just two buttons! The clip is convenient and bicycle fits all bike frames. Very good product for safe rides.