Just to add to Aries64's post....
The Panaflo Hydrowave bearing fan does use sleeve bearings. However, they have included a lubrication gel to increase the life span to that of a dual ball bearing fan. So you basically get the quieter operation of a sleeve fan with the life expectancy of a dual ball bearing fan.
In the UK Panaflo fans are much more harder to come by. I bought my sole Japanese L1A for about £6. So I tried out Coolermaster's equivalent of the Panaflo fan - a rifle bearing one. Those have model numbers starting with "R" and unfortunately come with LEDs, but those are easy to cut off if you so wish. I've found them to be very comparable to the Panaflo H's (which is fine for case fan if you have a fan controller) and they retail for £4-5 here.
Edit: Meant Panaflo H's...
The Panaflo Hydrowave bearing fan does use sleeve bearings. However, they have included a lubrication gel to increase the life span to that of a dual ball bearing fan. So you basically get the quieter operation of a sleeve fan with the life expectancy of a dual ball bearing fan.
In the UK Panaflo fans are much more harder to come by. I bought my sole Japanese L1A for about £6. So I tried out Coolermaster's equivalent of the Panaflo fan - a rifle bearing one. Those have model numbers starting with "R" and unfortunately come with LEDs, but those are easy to cut off if you so wish. I've found them to be very comparable to the Panaflo H's (which is fine for case fan if you have a fan controller) and they retail for £4-5 here.
Edit: Meant Panaflo H's...
