
I bought this primarily for use with multiple laptop hard drives (2.5"). Power and it was visible to the computer, but it accidentally disconnected. I thought the unit was defective, but with 5400rpm drives it worked fine even without an additional power supply. On the second try with a 7200 rpm drive it worked perfectly even without additional power. I have yet to try it with a 3.5" drive, but so far it's worked pretty well apart from initial issues with a 2.5" 7200rpm drive. Transfer speeds were with the newer SATA Well. devices, but I could definitely tell that one hard drive was using SATA II.