Ultra Products ULT31310 & Vantec NST-355U2 Drive Enclosures
 

Quote: "The fan cooled Ultra Products enclosure let the drive hit a high temperature of 40.6 C, while the passively cooled Vantec NexStar 2 let the drive hit a high temperature of 40.5 C in the vertical position and 43.9 C in the horizontal position. An insignificant difference of 0.1 degree was experienced in the vertical orientation, but considering the device with no fan ran cooler, it was surprising."

http://www.bigbruin.com/reviews05/hd...dex.php?file=1