UNIVERSAL SIZE: With the standard stem size (stem diameter: 11mm, stem length: 22mm), our hard floor casters are suitable for most office chairs as well as office chairs, desk chairs, gaming chairs, office chairs and desk chairs. Please measure the size of your chair casters before ordering to ensure they fit perfectly. Suitable for all surfaces: no more floor mats needed. With soft, heavy-duty polyurethane edges, the hard floor casters won't scratch or damage your floor. They do not leave marks on any surface. Perfect for expensive hardwood, tile, parquet, granite, and vinyl flooring. Easy to Install: With rust-resistant bearings, hard floor casters are easy to install and remove. No tools required, just remove the old office chair casters and click the replacement caster pin into the thread. With removable screws, the swivel chair casters can also be difficult to block crumbs, grit or hair and are easy to clean. Sturdy and Quiet: The office chair casters are made of premium steel and absolutely sturdy. When you slide the hard floor casters onto your office chair, you won't hear any noise. Even if you work or play at home or in the office, no one will be disturbed because no one hears it. Strong and durable: The wheel bearing balls are made of premium steel with good hardness, which avoids any deformation, and can support heavy objects up to 50 kg. Thanks to the high quality and toughness, our office chair casters can work for 8 hours/day 15 years.