Amazon.com: CMS 128GB mSATA 6GB/s Internal SSD Compatible with Lenovo ThinkPad T420 Series - C29 : Electronics
Lenovo ThinkPad T420 14.0 Laptop, Intel Core I7-2620M up to 3.4Ghz, 8G DDR3, 240G SSD, DVDRW, DP, W10P64-Multi Languages Support (EN/ES/FR), 1 year warranty Used Grade A - Walmart.com
New 2Nd HDD SSD Hard Drive Caddy Tray Replacement For Lenovo Thinkpad T420 T430 T510 T520 T530 W510 W520 W530, Internal Laptop C - AliExpress
Amazon.com: Bfenown 2nd HDD SSD Hard Drive Caddy Tray Replacement for Lenovo Thinkpad T420 T430 T510 T520 T530 W510 W520 W530, Internal Laptop CD DVD ROM Optical Modular Bay to 2.5 Inch
Amazon.com: CMS 128GB mSATA 6GB/s Internal SSD Compatible with Lenovo ThinkPad T420 Series - C29 : Electronics
For Lenovo Thinkpad T420 T430 T510 T530 W700 Optibay Aluminum 2.5" Ssd Case Hdd Enclosure 2nd Hdd Caddy 12.7mm Sata 3.0 - Hdd & Ssd Enclosure - AliExpress
I got free Lenovo T420 i put there Sata SSD 250Gb [Win 10 activated with original key for Win 7] i clean it and ive done little cooling mod [Temps drop -20C
ThinkPad T420 Hard Drive Replacement - iFixit Repair Guide