X201, I think from about 2010 or 2011. It's a little slow, but with the ssd, 8gb ram (instead of 4) and running Linux Mint, it sure isn't bad for a 10+
NOTEBOOK NETBOOK MINI PC PORTATILE LENOVO X201. RAM 4GB. i5. WINDOWS 10 PRO EUR 137,00 - PicClick IT
Lenovo ThinkPad X201 Business Laptop, Intel Core i7-1st Gen CPU, 4GB DDR3 RAM, 320GB HDD, 12.5 inch Display, Windows 10 Pro , Refurbished Laptop
Tutorial: How to upgrade the ram in a Lenovo x201 Laptop (in 1080P) - YouTube
GZEELE NEW Memoria RAM del Portello Della Copertura per Lenovo Thinkpad per per IBM X200 X200S X201 X201I X200T X201T 44C9555 44C0841 il MONTAGGIO della porta - AliExpress