Unless Sony makes proprietary drives all SATA laptop drives are the same size 2.5" and desktop drives are 3.5. Now they have MSATA SSD's but you can even get a 2.5" case for those. MSATA is popular on laptop because you are competing for real estate in those cases. SO the metal thing is just a bracket that hold the drive in so it's more secure. I replaced and Acer HD with a SSD and moved the HD to a second drive bay and the bay didn't have a SATA connector. It had some proprietary plug where a SATA adapter plugged into. I searched the world for that as Acer didn't really want to say they made since they didn't sell that model in the USA with 2 drives. I finally found would in Canada it was listed under accessories for my model and had an Acer part #. The Acer support said i couldn't have 2 drive on that model. Most companies don't like when you modify their non-configurable laptops. Some will refuse warranty work if you modify. When the Acer broke i set it back without the SSD and moved the hD back to the first bay.