ThinkPad T420 Hard Drive Replacement - iFixit Repair Guide
Bezel 2nd SSD HDD Hard Drive Optical bay Caddy Frame for Lenovo ThinkPad T420 T420i T430 T430i T510 T510i T520 T520i T530 T530i - AliExpress
2nd HDD SSD hard drive Caddy for Lenovo Thinkpad W510 T510 R400 R500 W700 W710 | eBay
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
Lenovo ThinkPad T420 (i3 8GB 512SSD) Linux KALI + TAILS Upgraded Fast +Warranty | eBay