Turn on one light and all your CatEyeSYNC™ lights come on. Using wireless technology, CatEyeSYNC™ lights make it easy to synchronize all lights to work as one. Check battery levels, customize modes, set braking mode and synchronize flash pattern preferences using your smartphone. Simple, superior 360-degree visibility is at your fingertips, with 500 lumens and excellent side visibility, the Sync Core gives you the power to see and be seen. Sync Core details (front): Max power: 500 lumens 5 lighting modes Dimensions: 41.5 x 33.5 x 93.5 mm Weight: 94 g USB charging (USB cable included) Charging time: 3 to 6 hours Details Sync Kinetic (rear): Dimensions: 74.5 x 26 x 28 mm 6 lighting modes Weight: 43 g USB charging Charging time: 2.5 hours