Upgraded accessories: the material is environmentally friendly PU material, and the bearing is made of carbon steel. SUPERIOR MATERIAL: Made of environmentally friendly PU and carbon steel,with wear-resisting and sound off wheel, giving you a quiet and convenient life. SIZE: The size of the luggage wheels replacement is replacement wheel OD: 50mm; wheel wide: 22mm; Center Bearing Internal Diameter Is 6mm/0.23inch please check the size carefully before placing the order. EASY INSTALLATION: You just need to remove the wheel with a hacksaw at the space, and then put on the new ones with the included accessories. APPLICATION: The luggage wheels replacement kit is suitable for luggage case wheels, swivel caster, roller skate wheels, etc. Colour:black Material:PU+carbon steel Package Contents: 2 x luggage suitcase replacement wheels 2 x axles and screws 2 x screw wrenches 4 x carbon steel bearing 4 x Gasket Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.