●Product Contents: Chain keeper 5.6 inches (142 mm) x 1, Dummy Rotor x 1; Material: Plastic ●[For thru axle] [Size] For 5.6 inches (142 mm), 5.3 inches (135 mm); [Inner Diameter] Approx. 0.5 inches (12.5 mm); [Compatibility]: For MTB Road Bikes; [Weight] Approx. 1.6 oz (47 g); [Caution]: Please check the size that it fits your bicycles ●This tool is for securing chains when the chain keeper wheel is removed for 5.6 inches (142 mm) and 5.3 inches (135 mm) and is used for thru axles ●[With Dummy Rotor] Prevents accidental grip of brake and pad (piston) ●(Easy to carry) makes it perfect for rings. It also makes a great companion for car washing and maintenance