[Design]: Exercise Bike Resistance Knob for most bikes and Exercise Bike.[Material]: Made of plastic and metal material, durable and functional.[Feature]: The knob small and portable, will not scratch your hands due to winding.[Easy to install]: The knob is easy to use and quick to install, it will not take up too much time for you, and it is very convenient.[Applications]: The Bike Knob Exercise Bike Accessory is widely suitable for strength and fitness equipment, exercise bikes, etc.Type:10 Gears/8 GearsColour:BlackMaterial:PlasticPackage Contents:1 * Exercise Bike Resistance KnobOnly the above package content, other products are not included.Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.