Wheel material: ABS tread + plastic wheel core, ABS Movable Medical Wheels are non-toxic, tasteless, tough and rigid, suitable for the medical industry. Casters Wheel Sizes Dia: 3 "-4" Casters Wheel UK Load capacity: 60-100 kg Flat-bottomed mobile medical wheel Wheel Material: ABS caster with PP core Bearing: Wheel axle Swivel flat plate medical caster