Shoe Covers Poly Pro, Blue & White. Shoe Cover blue 100% poly nonwoven material. White tread for traction, & elastic opening for a snug fit around the ankle. Widely used in clean room and hospital or laboratory situations, these shoe covers offer protection from dirt dust etc. (from your shoes to the floor). They can be worn by painters, plasters, movers etc. The white tread assists with traction on glossy surfaces.