Description: * Install the kit on 18 speed/24 speed bike. It is difficult to install, professional installation recommended(have electronic file English installation manual). * This kit is designed for 16"-28" normal bike, not for the bike that can shift gears. However, you can install the kit on the left hand side if your bike is18speed/24speed... you need to mount the freewheel on the left hand side on your rear wheel axis, and spot weld to secure it. After you have installed the kit , you can still shift gears on your bike. But if you don't know how to weld, we recommend you to buy our hub motor kit or our "mid-mounted" kit . Note: * Battery recommended for this kit: this kit is 24V, you need two 12V batteries, (lead acid or lithium), or one 24V battery. After they are linked together, the recommended capacity >15AH, working current need less than 20A. * NO batteries: the kit includes all the parts you need except batteries to convert the bike into electric bike.You need to buy the batteries by yourself. * Mount the batteries: We do not provide the battery box. But you can install it above the rear wheel on rear rack, or even make a box(need some DIY skills).You can design whether the batteries can take out or hard wired. * Installation Manual: The package does not include the installation instructions. If you need it, please contact our customer service to send the installation online to you This sample kit includes: * 1. 1x 24V 250W DC motor * 2. 1x Chain * 3. 1x Freewheel * 4. 1x Freewheel adapter * 5. 1x Motor controller * 6. 1x Mounting plate + bolts * 7. 1x Accelerator handle