The combination of Stem Caster Carts and Super Erecta Shelves are made of stainless steel and can be adjusted in 1 inch units. The casters come in a variety of types to suit your needs and are made of strong materials for long term wear and tear. The casters are available in swivel for easy movement, rigid or brake and all are non-marking and come with a 3 1/2 inch bumper to absorb impacts. Raised edges help prevent spills.