The Lian Li PC-A61 uses a tool-less HDD Tray system that makes hard disk installation quick and easy. The chassis supports 6 x 3.5" HDDs or 7 x 2.5" HDDs (one behind MB tray). These bays can be removed to make more room for high-end graphics cards. The thermal flow of this case has cool air pulled in through the 2 x 120mm fans and warm air is then pulled out by the rear 120mm fan.