HornetTek Viper 4TB (4000GB) 64MB Cache 7200RPM SuperSpeed USB 3.0/2.0 External Hard Drive (Black) - Retail w/1 Year Warranty Capacity : 4TB (4000GB) SuperSpeed USB 3.0 Interface (Backward Compatible with USB 2.0) Transfer up to 5.0Gb/s Fan-less cooling design keeps your drive running cool and quiet Support Windows 10, Vista, 7, 8 & Mac OS X or higher.