Features:1.Every product has a unique Manufacturing Part Number label on the inner package that proves it has been qualified,which include Part Number,Model Number and inspection date information;2.If you have any questions about the item,please provide us the Manufacturing Part Number for checking,your profits will be guaranteed.3. Product size: 51x80x50mm (length x height x wheel diameter), stem: 11x25mm (diameter x height).4.50mm Wheel Casters are the perfect replacement for damaged casters on office chairs.5.Specifically Designed to Help Protect Your Hard Floor Surfaces.6.Scope of application: all kinds of furniture, chairs, sofas, shelves, storage shelves, office furniture swivel chairs, sofa beds, furniture industry, machinery and equipment, etc.Note: This wheel is witouth brake.Specifications:Material: PU & Stainless SteelColor: Gray & Black & SilverSize: 5.1x8x5cm/2x3.15x1.96inch(LxWxH)Stem: 11x25mm (diameter x height).Weight: 462gPackage include:5x Office Chair Wheels