4U 15-slot Rackmount Chassis, support the front-accessible fan support ATX motherboard or up to 15 slot PICMG backplane impact disk drive bay can support three 5.25 "and one 3.5" disk drives unique hold-down clamp design with rubber feet to prevent the card from damage caused by power surges or vibration notification and HDD activity and improve system performance can access the front air filter for easy system maintenance can lock the front door, to prevent unauthorized access to flexible mechanical designed to support 300 W single PS / 2 and redundant ATX power 4U 15-slot Rackmount Chassis, support the front-accessible fan