We're not just casters anymore ... Master provides a variety of products to protect you and your office furniture. As the industry's leading supplier, we provide replacement casters for 99% of the office chairs on the market today. Master Manufacturing Company is a certified W.B.E. (Women's Business Enterprise) and a member of the National Minority Business Council. Founded in 1951, Master is owned by Iris R. Rubinfield whose leadership and commitment has developed a small, family-owned operation into a multi-million do/far business with unique, problem solving products. Located in an economic "Enterprise Zone" of Cleveland, Ohio, Master is committed to providing jobs for inner city residents with more than 98% of minority employees. Master's long-standing reputation for quality products and excellent customer service has made them a leader in the office furniture and supply industry. Safety Casters. Sold in sets of 5. Choose hard wheel casters for use on carpeting to provide smooth rolling and soft wheel casters for use on chair mats and other hard floor surfaces including wood, tile and linoleum to prevent damage. Internal Brake Casters prevent wheels from rolling freely when the user stands but provides smooth effortless rolling while seated. Available in standard neck size (5/8" diameter) or oversized neck size (1-1/2" diameter).