JetDrive 720 | SSD Upgrade Kits for Mac - Transcend Information, Inc.
Amazon.com: GODSHARK 7+17 pin mSATA to A1398 A1425 (2012 & Early 2013) Adapter for MacBook Pro Retina SSD Replacement, Mini PCIe SATA SSD Converter Card : Electronics
Amazon.com: MCE Technologies 500GB Internal SSD Flash Upgrade for MacBook Pro Retina (Mid 2012 - Early 2013) - Includes USB 3.0 Enclosure for Original Drive & Install Kit! : Electronics
Touch Bar MacBook Pro models have non-upgradeable SSDs, seemingly under-sized batteries - 9to5Mac
Replace your 2009-2012 MacBook Pro HD with an SSD
Mid-2012 Macbook Pro (SSD) Hard Drive Upgrade How To - YouTube