ASUS GX601 ROG Strix Helios HDD Cage Kit is a two bay 3.5” HDD cage kit for the Strix Helios series. The trays are tool-less drive tray design for 3.5" drives, simply attach them to the tray and slide them into the cage without using tools or screws. The 3.5-inch drive trays can accommodate 2.5-inch drives but you would need to use screws to secure them in place.