This is a Chrome 16 Tooth 4 Key type Free Wheel. A 4 Key Type Free Wheel is a removable with a 4 Key Tool. This Freewheel is for single speed bikes with 1/8" width chain. Check our Tool Section for 4 Key Free wheel remover Tool. This part is Perfect for your Fab Fixie Fixed Gear Single Speed Creation, Vintage Schwinn Bicycle Restoration or Custom Chopper Lowrider Cruiser Project.