The SY-MRA25052 has been designed to maximize space use by allowing up to eight 2.5? SATA III hard drives, while only consuming two 5.25? device bays. The enclosure only requires two SATA power connections to power up the eight 2.5? hard drives. With the mobile rack system, simply hit the eject button to unlock the access door, allowing the drive to be pulled out of the computer without having to dismount the drive. The rear of the SY-MRA25052 uses two MiniSAS connections to connect all eight SATA drives. It also has two 50mm cooling fans to pull cool air from the front ventilation slots over the drives and directs the warm air out through the rear ventilation slots. (MiniSAS to Port SATA Cable not included)