I have bought this hard floor casters on Amazon and received within 3 working days. The installation ran like with all other office chair casters easy to make. I have now to use for several months in and am more than ever convinced of this article, because the rollers pull neither stripes nor the extreme susceptibility to the passage of time the rolling resistance as nazulesen with so many other roles in the Rezesionen. For this reason a uneingeschrenkte buy recommendation.