This 4" x 2" polypropylene premium heavy duty swivel caster has a one piece plastic wheel ideal for use in wet and chemical environments. Polypropylene is non-reactive and non-marking.Our 44 Series casters are our most popular 2-inch wide industrial mobility solution. 44 Series caster rigs are manufactured in the United States, for expedited shipping and increased quality assurance. Many wheel options are also made in the US. Zinc plating provides an attractive finish which increases corrosion resistance and provides longer caster life.