Used to convert swivel workplace chair with casters to a desk bound chair with out wasting chair heightStandard B stem size diameter x height: 7/16 inch x7/8 inch (11mm x 22mm) , identical stem size as maximum casters2 inch Overall drift height - corresponding to most chair casters. Not compatible for chair which use 10mm Stem Caster2 inch Bottom Width x 1.33 inch Top WidthGreat for changing your rolling stool or workplace chair to a extra stable glide style, or replacing your old, worn glides. Turn a rolling chair or stool with casters into a stationary one with those glides without affecting the final chair top much.Colour: BlackMaterial: metallic + nylonDiameter: 50mmPackage Contents: 5pcs * Universal castersOnly the above equipment content, different products aren't included.Note: Light mirrored image and diversified reveals could cause the color of the article within the photo a bit of diversified from the real thing. The measurement allowed error is +/- 1-3cm.