This Western Digital 500 GB HDD is a great choice for those in need of additional storage for their laptop or PC. With a form factor of 2.5 inches, it is compatible with laptops and has an interface that supports SATA III, SATA II, and SATA I. It has a rotation speed of 7200 RPM and a cache of 32MB, making it quick and efficient for everyday use. The silver-colored hard drive has a California Prop 65 Warning due to containing a chemical known to the State of California to cause cancer. The item is used but has been tested and is in good working order. It comes as a single unit and has storage capacity of 500 GB. This internal laptop drive is perfect for those who need extra storage without upgrading to a larger solid-state drive.