Cateye Rapid X2 Kinetic USB Rechargeable rear light adds an additional dimension to the brightness and 180 degree visibility of the Rapid range. With an integrated accelerometer to detect the movement of the rider, the beam will automatically change from flashing mode to constant “Burst” mode for 2.5 secs under sudden deceleration. Make your presence known with the Rapid Kinetic X2. Ultra bright strip COB LED technology – 50 Lumen output. Supersonically welded for weather resistance. Versatile rubber band mounting system (12-32mm) for seatposts and seatstays. Kinetic Mode. Battery indicator. Battery Auto Save, converts to flashing mode so you’re never left in the dark.