Introducing the ToughArmor MB604SPO-B ruggedized mobile rack for hot-swapping 4x SATA/SAS SSDs and HDDs up to 9.5mm in height, and 1x Slim 12.7mm or Ultra-Slim 9.5mm CD/DVD/Blu-ray ROM optical disk drive reader for the external 5.25" bay. Featuring industrial full-metal construction inside and out, and designed for commercial applications such as military and medical systems, airborne and shipboard PCs, in-vehicle systems, servers, workstations, and mobile computer systems. Maintain optimal drive temperatures with the user-configurable 40mm cooling fan and plenty of ventilation holes throughout the enclosure. Advanced removable trays with anti-vibration protect drives in harsh environments, and built-in individual status LEDs give you drive updates at a glance.