Amazon.com: 2nd HDD SSD Hard Drive Caddy for Apple MacBook Pro Unibody Mid- 2012 A1278 13-Inch Laptop MD101LL/A MD102LL/A MD101 MD102, SATA3 Second Solid State Drive Enclosure, CD DVD SuperDrive Optical Bay New :
13-inch Macbook Pro main hard drive cable
Macbook Pro SSD Upgrade (2011/2012/2013) - YouTube