BORON ALLOY 10B21 STEEL LASTS UP TO 83% LONGER THAN STANDARD ROCKWELL 53 STEEL. LONG LIFE AND STRENGTH WITHOUT BEING TO THICK. Heavy duty twisted link Truck Tire Chain. 7.14mm thick. Two Link for consistent traction and smoother ride. Since this is a 2 link chain, cams are not on the side chain since the 2 link takes the space of where the cam would be. Recommended for over the road, chain law, semi trucks.For plowing or extended use, the Heavy duty truck tire chains below are recommended when available in your size.