[SAFE PROTECTION FOR ALL FLOORS]: These office chair casters are coated with an extra-thick polyurethane coating and guaranteed not to scratch or leave marks on any surface, even without the use of any chair mat. 100% safe sliding on wooden floors, parquet, laminate, linoleum, tiles, short pile carpet. (Not suggest to use on the carpet with more than 2cm wool) [UNIVERSAL FIT (NOT FOR IKEA)]: Our dual ball bearing office chair swivel casters are designed with standard size stems universal 7/16 inch (11 mm) x 7/8 inch (22 mm) rod, sturdy design (a set of 5) holds up to 700 lbs. Can swivel on almost any chair with wheels, whether it's luxury leather executive chairs or office chairs, computer chairs, gaming chairs. [SOFT AND SMOOTH ROLLING]: There are two wide double ball bearing transparent casters, precision bearings and a shock absorbing polyurethane tire that allow the casters to roll easily and smoothly over any surface without making any squealing or squealing noises. [VERY EASY TO INSTALL AND DURABLE]: Without any tools, remove the old office chair casters and push in the new wheels for a successful installation. At the same time, our transparent polyurethane casters are more resistant to acid, grease, water and some chemical substances, so the casters have a longer service life. wheel 50mmWheel width 55mmInstallation height 59mmInsert rod diameter 11mmPiston height 22mmMaterial: PU polyurethane + rubber + metalcolor: black + transparentPackage content: 5 * Office Chair CastersOnly the above package content, other products are not included.Note: Light shooting 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.