This item is the CD-ROM space 3.5" HDD mobile rack(built-in, desktop optical drive), which support 3.5" SATA HDD, tool free and scressless design make you can change your HDD You can install several mobile racks in your idle CD-ROM space, then you can efficient manage your material, for example, different operation system switched, different audio and video material storage. Simple and creative product appearance design, comfortable using experience, and stable performance