The NightRider Emax+ 150 EV taillight brings NiteRider quality to Electric Bikes integrating with the ebike battery. Compatible with 6 to 80 Volts DC the Emax+ powers on with the bike and offers 6 modes.For Electric Bikes w/cable for connecting to E-bike batteryTaillight powers ON with ignition switch2 Steady and 4 Safety Flash Modes w/ Built-in Mode Memory (remembers last setting)Voltage 6 to 80 Volts DCSecure seat post mount fits 22mm-34.9mmOptional Rack Mount with rubber mounting shims