Seagate BlackArmor NAS 420 4- Bay 2 TB (2 x 1 TB and 2 Empty Bays) Network Attached Storage ST320005SHA10G-RK Two Ethernet ports for local network connection, port failover and NAS to NAS replication Two USB 2.0 ports for external drives, printers and UPS and Four internal SATA II ports 7200 RPM, 2 TB, 32 Cache Designed for small business to provide optimum uptime and data integrity for up to 50 workstations. Supports Windows XP and Vista operating systems and Mac OS X 10.4.11 or later.