What secondary device have a metal disks mounted on the same spindle?

The secondary device with metal disks mounted on the same spindle is typically a hard disk drive (HDD). In an HDD, multiple platters are stacked on a spindle, with data stored magnetically on their surfaces. The read/write heads move across the platters to access or record data while the spindle rotates the disks at high speeds. This design allows for significant data storage capacity in a compact form.