We are offering twin wheels medical caster. Twin wheels medical caster wheel material:tpr,pa size:3" x 56mm ; 4" x 68mm ; 5" x 80mm loading capacity:60kg-120kg bearing type:delrin bearing type optional: plate swivel,thread swivel,stem swivel widely used as hospital bed caster,medical trolley caster, stretcher caster,laboratory casters,healthcare bed casters