Not for horizontal mount.
Needed to replace the top horizontal mounted fan on my antec 300 case. At full 1200 rpm the vibrations are terrible. My car keys laying beside my case, and the keys were touching the side panel. Turned my computer on, and it sounded like something inside my computer was falling apart. The sound was make by the vibration from the top mounted fan. That's just way too much vibration because the vibrations were transmitted all the way to the side panels.Used the supplied adapter for 700 rpm, and the vibrations were not near as bad, but the vibrations were still very noticeable on the top panel of the case. I was using the silcone mounting pins.The cougar fans seem to be high quality, and a lot of innovation went into the design of the fan. For horizontal mount, i can not recommend this fan. Will have to use double ball bearing fan for the horizontal mount.I really don't understand this fan. I have had a couple other cheap sleeve bearing fans mounted in the top of my antec 300 case, and they did not vibrate anything like the cougar does. Could just be a bad fan.Edit 1-11-14: mounted a global 140mm double ball bearing fan at 900 rpm into the top horizontal mount of my case, and i am happy to say no more vibrations.