Quiet effect: Quiet and does not hurt the floor. You will have the most stable and quiet casters that will not interfere with any work or disturb others. RELIABLE MATERIAL: The casters are made of high-quality PU material with high strength and wear resistance, which can be rolled easily and durably. Wide range of applications: suitable for furniture, office swivel chairs, computer chairs, small equipment, swivel chairs, swivel chair accessories, etc. Product specifications: Name: office chair casters Material: PU material central Total height: 55 mm / 2.3 Diameter: 50 mm / 2 Width: 38 mm / 1.5 Aperture: 8 mm / 0.31 in Hole depth: 26 mm / 1.02 in