MacBook Pro Mid-2012 SSD Upgrade: Reviews & Install Guide
INDMEM 512GB SATA SSD TLC Flash Drive Compatible for Macbook PRO 13 inch Late 2012 A1425 (EMC 2557), Early 2013 A1425 (EMC 2672), 15 inch Mid 2012 A1398 (EMC 2512), Early 2013 A1398 (EMC 2673) – BigaMart
2nd HDD SSD Hard Drive Caddy Adapter for MacBook Pro Mid 2012 replace UJ-8A8 DVD | eBay
MacBook Pro 13" Retina Display Late 2012 SSD Replacement - iFixit Repair Guide