Specification: Name:Chainwheel Protector Material:High Strength Plastic Size:40T,42T,44T,46T,48T,52T Package:1x Chainwheel Protector 5x Screws Chainwheel cover can prevent the ride in the process of the trousers is not easy to be transferred into the tooth plate gear, anti-break anti-oil effect. Product size style is complete, mostly for mountain bike / bus / folding bike, materials are plastic. Friendly reminder : the purchase of chainwheel cover before, please accurately measure the adjacent hole hole center size, the number of good teeth teeth, according to their own control to buy, the measurement is not accurate to install Oh! Purchase standard : measure the distance between the two holes in the center of the two holes, the number of good teeth teeth, the corresponding model to buy shield (cover on the number of teeth on the number of teeth). Common tooth number of teeth: 42 teeth 4 holes center size 10CM 42 teeth 4 holes center size 10.5CM 44 teeth 4 holes center size 10.5CM 44 teeth 4 holes center size 11CM 48 teeth 4 holes center size 12CM 48 teeth 5 holes center size 10CM 48 teeth 5 holes center size 9.5CM 52 teeth 5 holes center size 10.5CM How to Choose a protector correctly: 1.Countthe teeth of a chainwheel; 2.Confirm the mounting holes of a chainwheel; 3.Measure the center distance of each holes. (if can not choose the correct chainwheel protector, please