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 Gears8 Gears Colour:Black Material:Plastic Package Contents: 1 Exercise Bike Resistance Knob Only 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.