I have set of 3 vetroo fans. The price is for all and all working and functional. It is pretty quiet for cheap fans. I think is rated for 1500 rpm but don't hold me to it. You can look up the spec.

These were used as replacement my Thermalright assassin air cooler. I have the fans from the cooler if interested.

It comes with controller if needed. I didn't use it. I used my mbo. I would like to sell it as a set but if you have only need 2 or 4 let me know.