Climbing the "Water Fall" obstacle on Poison Spider Mesa gave us a good chance to learn what makes Pro Comp's new JK kit different from other long-arm kits on the market. Notice how the rear lower arm is seen dragging against the rock ledge in this photo. We questioned Pro Comp's resident Jeep expert about the material used for this part and whether or not it was designed to hold up to this type of abuse. Our suspicions were relieved when kit designer/fabricator Ryan Kennelly informed us that each boxed lower arm was constructed of hot-rolled, pickled, tempered sheet steel. The shape of the arm is triangular so as to distribute force loads while each side of the arm is further strengthened by a section of fish plating. The construction of this part is similar to that of a Trophy Truck rear lower link arm.