Features1DC brush motor, easy to control, can provide stable speed, sensitive braking and steering control. 2The motor shell is made of durable metal material, strong and reliable, protect the internal circuit, good for heat dissipation and avoid thermal overload. 39 - tooth sprocket for 410 chains, 1/2 inch (12.7 mm) pitch. 4Suitable for DIY bike lover, the drive compatible with the standard bike chain (1/2 inch separation distance ). 5Professional manufacturing, directly replace your old or broken one. 6Equipped with 12# power cord, easy to install and operateSpecificationItem type: Electric MotorMaterial: aluminum alloyWeight: Approx. 2210gColor: As picture shownType: Brush.Output power: 450WRated speed:420 RPMRated current: 25AChain wheel: 410-9TTransmission ratio: 7.18:1Sprocket output torque: 1.43 N.mPackage List1 xElectric Motor