The 5.5mm Square Alloy, Nickle, Chrome and Manganese Heavy Duty Tire Chain is the all new gold standard for tire chains. The chain is made of nickel, chrome, manganese, and other elements for maximum strength and durability. This chain is designed for the most aggressive and demamnding applications. The hardeness of this chain is 61 surface, 41 core and close to 10% case hardening depth. Square link design delivers more traction than the twist link chain and lasts up to four times longer. Comes with a cam stlye sidechain for easy tightening and boomer end fasteners.