Rollers now have zinc plated roller sections to help prevent rust and come with a protective wheelie case. Constructed of solid steel to provide a lifetime of trouble-free service. All models have rollers with smooth surfaces and rounded corners to protect flooring materials from indentations. Each roller section floats independently on the axle to automatically compensate for sub-floor irregularities. The end roller sections are recessed to inset the axle, preventing wall scuffing.