Hard drive caddy
What is a Hard Drive (HDD) Caddy?
Upgrading a laptop's hard drive is much simpler than it has been in the past, and most laptops today can be upgraded as a quick do-it-yourself project. Most laptops house their hard drives in a hard drive carrier called a Hard Drive Caddy or HDD.
Because the hard drive is inside of an HDD, you can easily remove or replace the hard drive in your laptop.Some HDDs are just a plastic bezel that attaches to the front of the drive, and some HDDs are more complicated and include a metal bracket, a plastic bezel, a drive connector, a cable and screws.
Most laptops have two bays; one for the hard drive, and one for the optical drive, although there are some that have three; two internal hard drive bays and one optical drive bay. Laptops with two internal hard drive bays would have an HDD for its primary/main hard drive and would require another caddy to mount the a second hard drive or solid state drive in its 2nd hard drive bay.
If you have a laptop with one hard drive bay and one optical drive bay, you can still add a 2nd hard drive internally.This is done by putting the second hard drive in the optical drive bay, and using a drive caddy specifically made to also fit the optical drive bay.