Long running battery-powered rear light with high waterproof rating of IPX7. Built-in "Brake Mode" function will alert others behind you of your deceleration. Built-in acceleration sensor for Kinetic mode (Brake mode)Automatically turns on Hi for 2.5 sec when bike deceleration is detectedWaterproof IPX7: Operates even after 30 minutes of submersion in a depth of 1 meterLong runtimes360 degree visibility5 LEDs3 modesMode memory functionFlexTight™ SP-11 bracket (Ø12-32mm)Snap System™