This is an SSD drive with a 400 GB storage capacity. The form factor is 2.5".
From SmartTeck
HPE 822784-001 internal solid state drive 2.5" 400 GB SAS -
Clove Technology
HPE 822784-001 internal solid state drive 2.5" 400 GB SAS
Athema Services
hewlett packard enterprise hot-plug ssd 400gb 2.5 inch sas interface,
Compadvance
HP Hot-Plug Ssd 400Gb