Auto Trac 912 Automatic Tightening Tire Chains I purchased these previously and stored them in a shed, but I am selling them because I replaced my car without using them. Even for those installing chains for the first time. Auto Trac is a diamond pattern chain that is strong against deep snow and skidding, supporting your snowy road driving more safely and comfortably. With two automatic tightening devices, "Auto Connector," even those who are installing tire chains for the first time can easily and securely install them. * 9mm ring adopted for narrow clearance * Easy and effortless with automatic tightening device * Securely installed with twin locks * Diamond pattern resistant to skidding * Ultra-lightweight * Comfortable ride ☆Size Chart☆ Standard Tires 215/70R15 215/65R16 215/60R17 225/55R17 225/50R18 235/45R18 Studless Tires 215/70R15 215/65R16 215/60R17 225/60R16 225/55R16 215/55R17 225/55R17 225/50R17 235/45R18