Durable and Flexible Ball Bearing: With double ball bearing swivel heads, heavy duty swivel casters can rotate up to 360 degrees and move freely. The swivel casters axle has double ball bearing swivel head, which is better than traditional solid bearings. Therefore, the furniture casters can be used for several years, even for frequent and commercial use. Sturdy and Durable: With the elasticity of the rubber casters combined with the metal structure which is sturdy and durable, the furniture casters work solidly. The polyurethane (PU) swivel casters neither scratch the floor nor leave marks on the floor and are safe for floors of all types. Flexible and Noiseless: The heavy duty trolley swivel casters can rotate 360 degrees. The industrial casters, like a skateboard, move freely and smoothly, even on a hard surface. The casters are sturdy and hardly make any noise. Easy to Use: The swivel casters come with the necessary screws and a screwdriver. You can assemble them very quickly.