Shimano MF TZ500 7 Speed Multiple Freewheel

Blacks

Key Features:A reliable 7-speed screw-on freewheelEngineered for smooth chain movement up or down the blockFor 7-speed gear systemsCan be easily installed onto compatible screw-on type hubSuitable for mountain bikes and a wide range of other cycles

Amazon

Efficient power transfer to the bike's drivetrain 14-16-18-20-22-24-34T Multi-speed freewheel