Connect and hot swap four 3.5in SATA III or SAS II hard drives to your computer system in three 5.25" bays with support for SATA 6 Gbps - Compatible with Servers Desktop computers with 3 available 5.25in bays and SATA or SAS hard drives - Trayless SATA Backplane / Hot Swap Bay / Backplane / Mobile Rack / SATA 6 Gbps / Key Lock / 70mm Fan - Onsite data backup as a secure alternative to cloud storage - Add a hot-swap bay to a server or workstation computer that you can use as a removable backup