Amazon.com: 2nd HDD SSD Hard Drive Optical Bay Caddy Adapter for Lenovo Thinkpad T400 T410si T410i T420si T430si and x200 x201 x220 UltraBase : Electronics
Lenovo Thinkpad X220 Hard Drive Replacement - iFixit Repair Guide
Installing a mSATA SSD into my ThinkPad X220 – Ioannis Karagiorgos blog
128 GB SSD Hard Drive 2.5 Inch Suitable for Lenovo ThinkPad X220 Tablet, Alternative Replacement Part, SATA3 Solid State Drive: Amazon.de: Computer & Accessories