Specifications:It is made of premium quality polyurethane and manganese steel material which makes it safe and durable for you to use.Also, it has a good shock absorption function and it is very easy to install and use so it would be very convenient for you to use.What& 39;s more, it would efficiently make the gate open or close more easily and quietly so it is very helpful for you to use.Additionally, this swivel caster is featured with special spring-loaded deign so it allows the gate to open and close the gate freely by automatically adjusting the height on uneven ground while eliminating the gate sagging.Furthermore, due to its high quality material and fine workmanship, it can be widely used in home and office equipment, communication equipment, ship assembly and other machinery industries.In summary, it would absolutely be a great gate accessory for you to use.Item Name: Gate Spring WheelMaterial: Polyurethane, Manganese SteelBearing: Double ShaftSpring Wheel Attributes: Shock-absorbing Spring FrameMaximum Load: 160Kg, 200KgFeatures: Spring-loaded Design, Fine Workmanship, DurableSize Details:4 Inch Spring Wheel: 13cm x 5cm x 31cm/5.12" x 1.97" x 12.20" (Approx.)5 Inch Spring Wheel: 15cm x 5cm x 36cm/5.91" x 1.97" x 14.17" (Approx.)Installation Height: 31cm/12.20", 35.4cm/13.93" (Approx.)Tire Diameter: 10cm/3.94", 12.5cm/4.92" (Approx.)Tire Width: 3.2cm/1.26" (Approx.)Notes:Due to the light and screen setting difference, the item& 39;s color may be slightly different from the pictures.Please allow slight dimension difference due to different manual measurement.Package Includes:1 x Gate Spring Wheel