Antec Tricool fan question

I have the Antec P180 case, and I'm starting to pick up various components to build a computer. I'm considering another Antec Tricool fan for intake, in the upper hard drive area.

On the Antec webpage, there are two different Tricool fans (well, three if you count the LED ones). One has a DB in the name, and the other doesn't. My first thought was the DB stood for double ball bearing, both the descriptions of both mention double ball bearing.

Does anyone know the difference? Is there a difference in noise level? How well they perform?