STANDARD SIZE- Our caster wheel rollers match most office chair models available, Standard stem diameter: 7/16 inch (11mm), stem length: 7/8 inch (22mm),Office Chair Caster Wheel Maximum Weight Rating: 50KG each wheel.EASY INSTALLATION- Just pull out the outdated chair wheel and it out, then push the rod of the hot office chair wheel into the slot till it is firmly fixed. It's like turning into a new chair.HIGH QUALITY WHEELS- Made of nice polyurethane. wear-resistant, light weight, clean to substitute and use, can preserve hardwood, laminate, ceramic tiles, slate and all different difficult materials floors from injury and scratches,The workplace chair wheel are consistently firm and straightforward to control when rolling.WIDELY APPLICATION- Suitable for most workplace chair,computer chair, gaming chair,executive chairs, paintings chairs, rolling stools, clean to slip on the challenging surface manufactured from carpet and polyurethane material, very appropriate for home or workplace use.Color: BlackMaterial: nylonPackage Contents:5 x wheelsOnly the above equipment content, different merchandise are not included.Note: Light reflection and various exhibits may cause the colour of the object in the picture a little various from the genuine thing. The measurement allowed error is +/- 1-3cm.