5★ Can be installed on standard bike frame easily.★ High starting torque, Max torque≥80Nm, good performance onclimbing.★ Double clutch is used on drive unit, more safety.★ Speed sensor and torque sensor can be applied, controllerintegrated.★ High efficiency, low consumption, long travel mileage.Countermark serial number on motor casing as following:BBS01 36V 250W15A 25km/h130100011. “BBS01”: motor type(speed sensor);”BBS02”: motor type(speedsensor with coaster brake);”BBT": motor type (torque sensor)2. “36V”: rated voltage; 250W: rated power.3. “15A”: limited current, 25km/h: max speed.4. “1301”: production date, produced in January of 2013.5. “0001”: serial number.Die-cast aluminum electrophoresis black treatment, workingenvironment temperature:-25℃-55℃, waterproof grade: IP65.1 Central motor1.1 Scope of application and numbering rule1.2 Material and waterproof grade