The U339-004 4-Bay USB 3.0/eSATA to SATA Docking Station connects up to four 2.5- or 3.5-inch SATA hard disk drives (HDD) or solid state drives (SSD) to an available USB or eSATA port on your laptop or computer. This lets you back up important data, retrieve data from an old hard drive, or store information on an external drive that you can take with you to another computer. Not only can you quickly access hard drive content without time-consuming internal installation, you can also clone a drive to as many as three others simultaneously. Cloning does not require the U339-004 to be connected to a host computer. Just insert the master drive into the master bay, insert the slave drive(s) into the slave bay(s), and press the Clone button twice. Red LEDs monitor cloning progress. The U339-004 accepts 2.5- and 3.5-inch SATA III, II and I hard drives up to 6 TB and will work with larger drives as they become available. This docking station supports USB 3.0 data transfer rates up to 5 Gbps, as well as eSATA rates up to 6 Gbps. Its UASP (USB Attached SCSI Protocol) feature reduces latency and allows the cable to perform up to 70% faster when connected to a UASP-enabled host controller. The U339-004 requires no software or drivers. It's compatible with all USB- and/or eSATA-enabled operating systems and backward-compatible with previous USB generations.