Fluir Single Speed Freewheel 18T

Fluir 18T Single Speed Freewheel, a bicycle component designed for single-speed drivetrains. It features an 18-tooth sprocket and is typically used on bicycles without multiple gears, such as BMX bikes, cruisers, or fixed-gear bikes that have been converted to single speed. 

This specific part is a screw-on type freewheel, which means it threads directly onto the hub of the bicycle's rear wheel.