3.5" Front Panel 4 x HDD Power Switcher is 4pcs HDD power switcher. It was installed in 5.25" CD-ROM space (need an idle CD-ROM space), and has 4pcs separate power supply interface and switch, you can control your HDD power supply in computer chassis at any time. It also can be called an energy saving device for HDD, as it is a green product and can reduce the power loss, protect your HDD and extend life time. Of course, you can use it to install different operation system or software environment, then you can switch to different operation system and software environment easily! For the fans with these requests, this product is absolutely the best choice!