This 4" x 2" Polyurethane on Steel Rigid Caster features a weight capacity of 700 lbs. The 95 Shore A polyurethane elastomer is chemically bonded to a semi steel wheel core and has an operating temperature range of -40 to +180° Fahrenheit. Polyurethane on steel wheels offer high weight capacities while providing good floor protection, and works well in both indoor and outdoor environments. The wheel core can rust when wet, so this wheel is not recommended for applications which operate where water is present.
For more info, check out Caster Wheel Types.