Amazon.com: MCE Technologies 1TB Internal SSD Flash Upgrade for MacBook Pro Retina (Mid 2012 - Early 2013) - Includes USB 3.0 Enclosure for Original Drive & Install Kit! : Electronics
Does the mid-2012 13 MacBook Pro have an M.2 slot that I can use for an Intel Optane memory upgrade? - Quora
mSATA SSD Installation with an adapter on Macbook Pro 15 (Retina Mid 2012) - YouTube