The new ACE 40 x 20mm case fans stand out for their high quality and amazing good looks. Instead of using sleeve bearing, these fans use dual ball bearing for all their construction. Dual Ball bearings last much longer than the cheaper Sleeve bearing, which most other fan brands are using. We have 10 total new fan colors and all these LED and UV fans are chosen for eye-candy inside your case. The plastic frames are either UV colored or a smoky clear and have a much nicer look than others in the market. These are a also real quite when used with a fan controller, or a 7V, or 9V adapter cable.