The Cateye ViZ 100 Rear Light is a 200 lumen USB rechargeable light with excellent side visibility. A versatile rubber strap allows for quick and easy attachment/removal from the seat post etc. Key Features: 3 LEDs (100 lumens) Focused lens for maximum visibility Highly visible during daytime Superior 300 degree visibility Long rear beam projection OptiCube™ lens technology Lithium-ion rechargeable battery USB rechargeable (Micro-USB cable included) Low battery indicator 4 modes: Constant / Flashing / Group Ride / Daytime Hyperflash Mode memory function Battery Auto Save (The mode automatically changes to flashing when the battery power gets low.) New seat post bracket SP-15 which also fits contemporary (Kammtail) aero seatpost Snap System™ bracket Designed in Japan Runtime: Constant (15 lumens) 5 hrs Flashing (10 lumens) 70 hrs Group Ride (35 lumens) 11 hrs Daytime Hyperflash (100 lumens) 15 hrs Charging time (From empty) 3 hrs Technologies: Opticube™: Our proprietary OptiCube™ lens technology maximizes brightness for greater visibility. Snap System™: Allows riders to place rear lights on various locations in both horizontal and vertical orientations. Side Visibility: Provides 300° visibility from the side to increase safety. Low Battery Indicator: Alerts when remaining battery gets low. Daytime: Can be used in the daytime. All Weather IPX4: Can be used in rainy weather.