The Obsidian Series: Designed by builders, for builders. Obsidian Series 900D is for serious builders with big projects. Do you want to design your ultimate dream PC? Add state-of-the-art liquid cooling or air cooling? Build a quadruple GPU, dual CPU graphics powerhouse? Or, just create a monster file server? If these are the kinds of questions you’re asking yourself, you need a 900D. Serious Expansion Flexibility for Serious Builders We don’t need to tell you that there’s no such thing as too much room. We’ll just let the numbers speak for themselves: Ten expansion slots Fits up to nine hard drives or SSDs, with three hot-swap mounts Four 5.25” optical drive bays Room for dual power supplies model : CC-9011022-WW tag : Computer Cases