The NF-B9 is a 92mm fan that is very different from every other fan out there on the market today, it has teeth on the blade, well technically they are called Vortex Control Notches, but they look like teeth to me. Anyway, the NF-B9 also has beveled blade tips, and Noctua's own SC Drive system and SSO bearing to make for one very quiet fan that still can move quite a bit of air.



Link: DSM