The Zalman ZM-HE350 U3 and U3e External HDD Enclosures are all about flexibility. The Zalman ZM-HE350 U3 offers a USB 3.0 SuperSpeed connection, with complete backwards compatibility to USB 2.0 and 1.1, while the U3e adds eSATA connectivity to the mix. Whether you need blazing USB 3.0 and eSATA transfers, or connectivity to an older machine, the ZM-HE350 U3 and U3e have you covered.