This BUSlink 4-Bay RAID hard drive supports large capacity and USB 3.0/eSATA interface. It supports Intelligent RAID function: RAID 0, RAID 3, RAID 5, RAID 10, and Large. Removable HDD trays support hot-plug replacement of drives (only for RAID with redundancy mode). HDD intelligent sleep function is supported. The LCM display and buttons support convenient setting of RAID modes and status display. Optional password allows locking of RAID settings. Cooling fan maintain safe operating temperature. Skid proof and shockproof rubber feet mat ensure safe operation. CipherShield design features a chip embedded in the access key which matches the AES encryption module on the controller board. The drive will automatically lock down its content once the key is unplugged, or power is shut off. And without the access key, data will not be seen or accessed in the event of theft or loss of the external drive. Data stored on the hard drive are safeguarded by hardware-based National Institute of Standards and Technology (NIST) certified industrial strength AES (Advanced Encryption standard) cryptographic engine. The advantage of hardware encryption over software encryption is that you need not be concerned about Trojans/viruses or software upgrades, which results in a decrease of total cost of ownership. Since CipherShield encrypts data independent of the operating system; removing the drive and connecting it directly to the SATA BUS will not defeat the encryption. Unit is bundled with two keys and registration is required for key duplication.