Upgrade Your Macbook Pro (SSD Upgrade, RAM Upgrade, Optical Drive Bay Adapter) - YouTube
Amazon.com: HDD SSD SATA Hard Drive Connector for Pro 13" A1278 Pro9,2 Mid 2012: MD101LL/A MD102LL/A 923-0104 923-0741 821-1480-A 821-2049-A 821-2480-A : Electronics
Apple MacBook Pro A1278 MD101LL/A 2012 Core i5 2.5GHz 8GB RAM 256GB SSD – Coretek Computers
for Apple MacBook Pro Unibody Mid-2012 A1278 A1286 13" 15" Laptop Internal 2nd 240GB 240 GB 256GB SSD SATA 3 6Gbps Second Solid State Hard Disk Drive DVD Optical Drive : Amazon.in:
MacBook Unibody Model A1278 Hard Drive Replacement - iFixit Repair Guide
Installing SSD (Solid State Drive) in Your MacBook Pro 13" or 15" Unibody : 24 Steps (with Pictures) - Instructables