Industrial medium duty Grey Rubber Castors. This medium duty grey rubber caster wheel has uses that include warehouse trolleys, engineering, transport and staging. The elastic blue rubber on these medium duty castors help protect floors & reduce noise. Our high quality industrial medium duty castors and wheels range will let you select the best caster wheel for your application. With swivel, rigid, swivel with brake and bolt hole solutions available, make sure we are your first option for a solution.