https://wccftech.com/icy-docks-tougharmor-mb839sp-b-allows-you-to-shove-2-5-inch-storage-into-pcie-expansion-slot/

Since both NVIDIA's SLI and AMD's Crossfire multi-graphics card systems are losing popularity, systems have fewer spare expansion slots in our full-size ATX PCs. Icy Dock has introduced the ToughArmor MB839SP-B adapter, which turned a PCIe 1x expansion slot into a hot-swappable 2.5-inch drive bay for SATA drives.

The ToughArmor MB839SP-B rugged removable drive bay for 2.5" SATA hard drive and SSDs (9.5mm height). Utilizing the standard PCIe 2.0 interface and this removable bay only takes up a single PCIe expansion slot, the MB839SP-B allows your system to offer an additional hot-swappable drive bay for hard drive disks (HDDs) and solid-state drives (SSDs) even when your system may not have an open SATA port or an empty drive bay. Because the single PCIe port handles both power and data, there is less clutter as there is no need to run a SATA data cord or a power cable to the hot-swappable drive. This adapter fully supports hot-swapping drives with its removable drive tray.