All steel, trouble free construction guarantees a lifetime of maintenance free service. Steel will not crack or chip as cast iron can. Nothing can go wrong with solid steel roller sections?no bushings of any sort to come loose. Added to this is the famous Gundlach craftsmanship which is applied throughout to all details of construction. Used on: Linoleum, vinyl sheet goods, rubber tile, vinyl tile, cork tile, wood block tile, roofing systems and waterproofing membranes. For perfect installations, use the size model specified for these materials by their manufacturers.