2. 12 x 3.5" Hot-swap SAS / SATA Drive Bays
3. Hard Drive Backplane with 2x 28-Port 3Gb/s SAS Expander Chips & Enclosure Management
4. 3 x 80mm 6300 RPM Fan
5. With Universal I/O (UIO) Card:
3 x Full-height, Full-length I/O
3 x Low-Profile Expansion Slots
Without Universal I/O (UIO) Card:
4 x Full-height, Full-length I/O
3 x Low-Profile Expansion Slots