About the Topeak Helmet Rear Light Introducing the Topeak Tail LUX. This is the perfect product to have, if you are traveling in a high traffic area. Whether its riding home in the dark winter months, or going for an evening training ride, you can be seen from top to toe in dark, with this extra light attachment. You have the option of attaching it to other topeak items such as a pannier rack, saddlebags or pannier bags the Tail LUX light is a versatile light. The ultra-bright, compact and lightweight light provides excellent visibility keeping you visible on the roads to pedestrians, vehicles and fellow cyclists. The light comes with two modes, flashing and constant, which gives you an option for when you are in different situations. Weighing in at 14 grams the light isn\\\'t going to weigh you down. The light takes a simple CR2032 battery (1 included) and has a battery life of up to 100 hours. Overall this is a handy little light to have as it makes people and drivers around you more aware of your position on the road. Key Features Light Source: LED Brightness: 0.5W Power Source: CR2032 Battery Run Time: 50 to 100 Hours Mounting: Mounts on helmets, Topeak bags or racks Light modes: 2 modes: Constant and Flashing Dimensions: 3cm (H) x 3cm (W) x 1.7cm (D) Front/Rear/Set: Rear Weight: 14 grams Lighting Buying Guide