Endorfy Signum 300 Air is laid out well, pleasant to the eye and as strong as the armor on a high-level tank. Inside, you'll fit everything you need to work, play, and create - and with the tempered glass side you can easily show it off to your friends. The interior of Endorfy Signum 300 Air is also impressive. This roomy beast can easily accommodate two 3.5-inch hard drives with another two 2.5-inch ones (or four small drives instead). Not only that, but you can also pack a tall CPU cooler, a 350 mm long graphics card, and as many as eight fans.