Material: Swivel casters are soft rubber and TPE material wheels, super quiet, won't disturb anyone while working, high elasticity, 360 flexible use. Bearings design: Ball bearing, integrated bearing, steel ball steering design, sealed bearing has low friction resistance, flexible bearing, can rotate 360 degrees, stable, high temperature resistance, high speed, dustproof and non-stick , and can be used for a long time Built-in silent bearing, very quiet and durable. It is the ideal choice for all DIY furniture with movable casters. Specifications: Drum diameter: 25 mm / wheel width of each drum: 13 mm / threaded screw height: 15mm, compact in shape, including 4 casters with M6 threaded screw, and easy to install. Suitable for a variety of floors: Made of soft rubber, which is soft and won't damage the floor. Rubber casters have elasticity, toughness and durability. Suitable for all types of floors, such as ceramic tiles, cement floors, marble, carpets, parquet floors, etc. Wide range of uses: Furniture casters are ideal for indoor or outdoor use. Mobile casters can be used in homes, lawns, factories, stores, businesses and hospitals. Swivel casters ideal for furniture and other small movable furniture (such as coffee tables, desks, shelves, shoe cabinets, shopping carts, transport carts). Size: 1 inch universal screw / (M6*15) Color as shown Quantity delivered: 4 pieces