Material: Caster sleeve is made of PP/PA material, and strong, not easy to be , can be used for a long time Dimensions: Our overall length of the caster sleeve is about 43.5 mm (1.71 inches), the diameter is about 25 mm (0.98 inches), and the hole diameter is about 11 mm (0.43 inches).Compatible with 7/16 inches stems Wear : Black caster rod insert sleeve protect chair legs and floors from wear and tear. Plastic caster sockets mount securely to the chair legs and are not easily dropped Easy Installation: These plastic caster bar socket insert covers are very easy to install and remove. Perfect for all kinds of universal casters. Great protection for your universal casters Package Includes: 40pcs plastic caster sockets. Caster stem sleeve replacement parts for casters of chairs, tables, bookshelves, filing cabinets, machinery and more Color:Black Material:plastic Package Contents: 40 * Caster Socket 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.