Tray-less 4 In 3 Sata I & II Fits 4 x 3.5 SATA HDD into 3 x 5.25 Device Bays Screw-less, tool-less design for genuine plug & play and hot swap use Compatible with SATA 6 Gb/sec Stylish aluminum construction for durability and heat dissipation 80mm cooling fan for maximum air flow