This 4 bay 2.5 inch to 3.5 inch SSD hard drive enclosure caddy chassis is an internal mounting adapter bracket made of aluminum alloy. It supports 4 x 2.5-inch notebook hard disks or SSD solid state hard disks for installation and is designed to be installed on the 3.5-inch hard disk slot inside the desktop case to expand the 2.5-inch hard disk. The package includes 1 x hard drive bay, 1 x accessory pack, and 20 screws. The product dimensions are 75x66x13mm/2.95x2.6x0.51in and it weighs 143g.