DreamWare Computers posted a review on the Vantec NexStar SX 2.5" Drive Enclosure
A quote from the article:
Vantec NexStar SX 2.5" Drive Enclosure Review
For those who are on the go and need to carry large amounts of data with them, more than a USB stick can hold, then a 2.5" external drive is a must-have. One thing that makes these a much better option than a full sized external drive is the lack of needing to carry a power adapter. Because of the power requirements of 2.5" drives they can be entirely powered through the USB bus! This means you only need to carry one small cable with the enclosure and not a big and bulky adapter too!
Vantec NexStar SX 2.5" Drive Enclosure Review