We also sell a set that includes a 3-speed free cassette and shift lever that can be used directly on a single-speed bicycle frame.
 With this set, the other parts are
 ● Chainring for shifting gears
 ● Rear derailleur
 ● Gear shift chain
 ● Shift wire


 By adding these four parts, you can make your bike have multiple gears. Most regular bike shops should be able to provide and install them for you.
 *It's even better if you lightly file down the drum-shaped end of the shift cable to give it a rounded shape.
 *The 3rd speed freewheel is a fixed type, so you will need to disassemble it to remove it.