QNAP TS-439 Pro Turbo NAS (Network Attached Storage) - Superior performance server with iSCSI for Business 4-bay model of the worldwide award-winning Turbo NAS Series Superior performance for massive data sharing Powerful all-in-one business server features Advanced RAID data protection, built-in iSCSI target service AES 256-bit volume-based encryption, and rock-solid hot-swappable hard drive design