Transcend USB 3.1 Hard Drive is Built with a durable anti-shock rubber case, the iron grey 4TB USB 3.1 External Hard Drive from Transcend combines a 4TBstorage capacity with a USB 3.1 interface, 256-bit AES file encryption, and military-grade shock resistance. The internal 2.5′′ hard drive receives further protection from a suspension system, while a one-touch auto-backup button helps to create a second copy of your data and a quick reconnect button re-enables the removed hard drive without needing to remove and reinsert the USB cable. Power is provided via the USB bus, and compatible operating systems include Windows, Mac, and Linux.