The 301’s 3mm tinted tempered glass allows users to admire their builds inside and out. And the tool-less feature doesn’t even require thumbscrews with this elegant tempered glass side panel.Simply remove by pressing the button on the handle. The 301 has one 3.5” /2.5” HDD tray, and supports up to three 2.5” SDDs. There are also four PCI-e slots at the rear and a separate PSU chamber, which provides more expandable options in a compact size. The 301 supports up to a 240mm radiator at the front, and a 120mm radiator at the rear. It can also accommodate two 120mm fans at the bottom.