P09712-B21 480GB is an SSD type hard drive which can fit 480 GB of data. This model has a 2.5" form factor, which is common for SSD drives.
From SmartTeck
HPE P09712-B21 internal solid state drive 2.5" 480 GB Serial ATA -
Athema Services
hp ssd 480gb sata 6gb/s mixed use **new retail** p09712-b21 - eet01