Robust All-Weather Design The E-Lume 600/Cosmo 60 light combo from Serfas is a highly capable light set offering, good value and performance. Encased in a highly durable extruded aluminum body, the E-lume unit is protected from all weather conditions while remaining light and compact. The Cosmo 60’s 270 degree high visibility design offers maximum safety and reliability. Versatile and Adjustable Be it Commuting, Gravel, MTB, or Road riding; the E-Lume 600/Cosmo 60 light combo will fit your needs. The E-lume 600 features an adjustable quick-release handlebar bracket that can fit bar diameters from 22mm up to 31.8mm. The Cosmo 60 rear light comes with multiple rubber inserts and O-rings to easily fit most seat posts. Long Life Runtime With efficient integrated batteries that are micro USB rechargeable, you spend more time on the road at any time of day. With both solid and flash modes there will always be an option for you, no matter where you are. A handy blue LED charge indicator gives you vital charge information and increases safety out on the road, no more sudden flat battery situations.