10MM OR 11MM - Our PVC coated casters are available in two sizes. Therefore, please determine the pin size required to the nearest millimeter. 90% require 11 mm, except, for example, office chairs from the Swedish furniture manufacturer.HARD BRAKING - To prevent unintentional rolling, the chair with the hard floor castors fitted only rolls under charge. Perfect at the desk, at the table and for games.MAXIMUM PROTECTION - With the 50 mm castors for office chairs, you can move flexibly and protect surfaces such as parquet, laminate , tile, carpet or stone floors thanks to the soft PVC coating.BEST QUALITY - The two wheels on the steel axle ensure comfortable rolling. The sturdy plastic housing sits above and together with the bar ensures a stable connection to your chair.