FEATURESa Connect/pair with other NiteLink(TM) compatible lights (lights sold separately)a VerifiR NFC Technologya Power ON/OFF button, Light Mode Toggle Switch, and Turn Signal Indicator Buttonsa Replaceable CR2032 3V Batterya Fits up to 31.8mm handlebarsa Weight: 53ga Water / Dust Resistant IP64 Rateda Equipped with NiteLink(TM) Wireless TechnologyBATTERY LIFE2-3 YearsEQUIPPED WITH NITELINK(TM) WIRELESS TECHNOLOGYNiteLink(TM) Compatible Headlights (Lights sold separately):a Lumina(TM) Max 1500 Front Bike Light with NiteLink(TM)a Lumina(TM) Max 2000 Front Bike Light with NiteLink(TM)a Lumina(TM) Max 2500 Front Bike Light with NiteLink(TM)a Lumina(TM) Pro 1300 Front Bike Light with NiteLink(TM)NiteLink(TM) Compatible Taillights:a Omega(TM) 330 EVO(Must be paired with a NiteLink(TM) compatible headlight to access wireless control)