Amazon.com: New 2nd HDD SSD Hard Drive Caddy for Lenovo Thinkpad T420 T430 T510 T510I T520 T520I T530 T530I T530U W510 W520 W530 W700 W701 R400 R500 12.7mm high with Matched Faceplate/Bezel :
Lenovo Thinkpad T61 256GB SSD with Caddy, 7 Pro 64-Bit and Drivers Preinstalled | eBay
Lenovo THINKPAD T61 - 240 GB SSD SATA Hard Drive | eBay
I “think” you enjoy this… T61 (256 Gb SSD Debian 10, RAM 4 Gb) and E14 2021 (upgrade with RAM 16 Gb, 1 Tb M.2 for Windows 11 and 256 Gb SSD for Debian 11, all Crucial) : r/thinkpad