Specifications: Diameter: 3.9 inches (100 mm); Thickness: 0.6 inches (15 mm); Compatible casters 2.8 - 3.9 inches (70 - 100 mm); Can be used as an earthquake prevention tool. This product prevents the caster from shifting, but it does not completely prevent movement or falling. Depending on the floor material used and the environment, the product may not be able to perform sufficient effects. Please use it with other earthquakes as a safe measure to move and prevent falling. ※We cannot guarantee the case of earthquakes or other natural disasters.