HPE 512545-S21-RFB is a refurbished hard disk drive for adding storage in a compatible system that supports hot-swap drives. The listing identifies this particular item as a 72 GB, 2.5-inch HDD.
Its hot-swap designation describes the drive format offered; the listing does not specify supported systems or provide further interface details. This is a refurbished item, as stated in the product listing. The product is presented as a storage component, with capacity and form factor that help identify the particular variant.