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.Deep groove ball bearings, slide flexible, compression wear.4.Made of Plastic and steel,good replacement for your damage one.5.It is suitable for slide Bathroom door, closet door glass sliding doors.Specifications:Material: Plastic + SteelColor: WhiteSize:Inner Diameter: 0.4cm/0.16inchOuter Diameter: 0.2cm/0.08inchWidth: 6.5-7.4mmWidth:0.65cm/0.26Weight bearing: 27kgWeight: 23gNote: The in-line bearing cannot be removed.Package include:4 x Nylon Pulley Wheel