From Manufacturer
The black 1U 3.5" 4-Bay Tray-Less Storage Server Rackmount Chassis from iStarUSA is a compact chassis with tray-less and hot-swappable 3.5" bays that make it a storage server. This compact chassis has a built-in 250W flex power supply unit and four peer-to-peer SATA ports on the backplane to support SAS and SATA hard drives.
Four 3.5" tray-less and hot-swappable drive bays
Power and HDD activity indicators
Four peer-to-peer SATA ports backplane
Metal key lock
Built-in 250W flex PSU