Weight Approx. 480g Size L: 55-61cm M: 54-58cm(EN1078) 55-59cm (CPSC1203) Bicycle, Skateboard, Roller Skating, Hoverboard, E-bike, etc. The front warning lights work together with the 270° tail lights, to protect users security in all directions. When the built-in gravity acceleration sensor detects a significant deceleration, the front and tail lights will be highlighted for 8 seconds to draw front and rear vehicles’ and pedestrians’ attention.