Macally 3.5" USB2.0 HDD Hi-speed HDD external storage enclosure, Aluminum. Size: 88.9 mm (3.5 "), Hard drive interface: Ultra-ATA/133. Interface: USB 2.0. Compatible operating systems: Mac OS 9.2, Mac OS X v10.1.5 Windows 98SE / 2000 / ME/ XP, Minimum system requirements: USB. Weight: 0.59 kg. Power requirements: 100-240 VAC