Soft Tread Casters For Hard Surface Floors (4) Twin wheel for easy mobility on hardwood, ceramic and marble as forgiving on hard wood floors. Available in black only , Will not scratch or scuff floors Will not scratch or scuff floors if floors are kept clean Dual wheel polyurethane casters are softer than your standard caster, Casters rotate full 360 degree for smooth movement Simply pull out old casters and hammer in new ones with rubber hammer or by hand