Apple has a well-earned reputation for being restrictive on hardware upgrades, for anyone who is a little handy with components and would like to upgrade the Mac Pro or Mac book they own, is going to be limited to a few options. Recently, Apple has restricted this even more with soldered on RAM or sealed iMac's that are very risky to open up. For some time now, Apple has used a proprietary M.2 style connector format using a 12 + 16 Pin arrangement on their M.2 drives, either made by Toshiba or Samsung (SSUAX or SSUBX).