The casters operate very smoothly and are quiet. Since the outer molding is soft, they do not make the loud that standard casters make. The bearings are fully enclosed and it is important because the casters will not pick up the floor, if you have pets there are no more worries about the wheels getting clogged up. Features - - Material: PU. - Size: 8.00 x 7.00 x 3.00cm/ 3.14 x 2.75 x 1.18 inch. - These premium casters are especially designed to protect carpet, hardwood floors, , tile, and other floors. - Slide and glide around in total silence with our swivel casters instead of squeaky rickety office chair wheel. - Widely used in trolleys, workbench, furniture, shelves and other items commonly found in workshops, garages, kitchens, and offices, indoor and outdoor. - These casters are widely used, used for cart, shelf, wooden cabinet, furniture, home appliances, etc. - Smoothly moved with no marking, won't harm your wooden floor, no noise, the surface of the rubber wheel is and better protects the ground, silent and practical. Package list: 4 x casters