Installing MacBook Pro 13" Unibody Late 2011 Dual Hard Drive - iFixit Repair Guide
MacBook Pro 13" Unibody Late 2011 Hard Drive Replacement - iFixit Repair Guide
Amazon.com: 2nd 2.5'' SATA HDD SSD Hard Drive Disk DVD CD ROM Optical SuperDrive Caddy Tray Adapter for Apple Unibody MacBook/MacBook Pro 13 15 17 Early mid Late 2008 2009 2010 2011 2012.etc : Electronics