The Thule Easy-Fit snow chains are the easiest snow chains to use from Thule. The Easy-Fit snow chains are constructed from a combination of steel chains and support bars, with an aluminum main bar. The heart of the Thule Easy-Fit snow chains is the automatic tensioning system. The operation of the automatic tensioning system is easy. Wrap the chains of the Easy-Fit snow chains around you tire then depress the integrated pedal. By depressing the integrated pedal, the Easy-Fit snow chains will automatically tighten itself around the wheel when the car starts moving.