MB971SP-B 2.5"/3.5" SATA HHD & SSD Drive Caddy for 5.25" device bays. The DuoSwap is capable of storing 1 x 2.5" & 1 x 3.5" SATA SSD/HDD and uses a tool-less and hot swappable drive installation to easily exchange either drive in just seconds. It has other benefits such as: individual LED's, power button, and eject button. A 2 part anti-dust cover protects system internals even when a small 2.5" SATA drive is used. Having an easy way to use hard drives without the hassle of installing or removing makes it a must have accessory for any personal PC, Lab testing PC, or HDD duplication system.