An improperly aligned chain and sprocket set will cause both of them premature worn out. Now You can probably correct this at home, to check the alignment of your chain and sprocket. Its basically a bracket that goes onto your rear sprocket then a long thin rod as a reference line to see if your chain is properly aligned Specification Product Name: Chain Alignment Tool Color: Red Material: 6063-T5 Aluminum Intended Use: Modification/ Enhancement For Motorcycle, Bicycles and ATVs Fitments: Universal Motorcycle Features: Quick and accurate alignment Tool body clamps squarely to rear sprocket so the alignment rod will indicate sprocket alignment to chain Attention: Clamp machined tool to rear sprocket and move rear wheel until the alignment rod lines up with the front sprocket. Use on left or right side. This is an essential tool to have for anyone working on their own machine. Quick and accurate alignment Tool body clamps squarely to rear sprocket so the alignment rod will indicate sprocket alignment to chain Note: 1.We provide clear pictures, measurements where possible. Please check as much as possible to make sure the item is the one that you need. 2.Please allow 0.5-1 inch difference due to manual measurement.(1inch=2.54cm) Highly Recommended Package Include: 1x Chain Alignment Tool