The Serfas E-Lume Lightset Combo offers the E-Lume 350 Lumen output Headlight, paired with the Cosmo 15 Lumen Taillight. The Headlight offers up to 80 hours of runtime with a daytime flash mode and features a durable Extruded Aluminum Body with handlebar bracket, a backlit button indicates charge status and low battery while the integrated USB rechargeable Li-ion battery charges from flat in just 2.5hrs. The Cosmo Taillight features a 15 Lumen output, 3 modes and durable ABS construction with IPX3 Water resistance. Three LED’s provide 5 Lumens of brightness each for easy visibility. Last memory mode allows you to pickup where you left off. USB charges from dead flat in just two hours.