Wheel Chocks (Caster Stoppers) 3.0 inches (75 mm) Diameter 10 pcs. Specifications: Diameter 3.0 inches (75 mm) Thickness: 0.4 inches (10 mm) Compatible Casters - 3.0 inches (75 mm) / For securing casters and as an earthquake prevention. 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.