16GB KIT (2 x 8GB) for IBM Lenovo ThinkPad T Series T420 T420i T420s T520 T520i. SO-DIMM DDR3 Non-ECC PC3-10600 1333MHz RAM Memory. Genuine A-Tech Brand. at Amazon.com
Lenovo Thinkpad T520 Disassembly video 4K, upgrade RAM & SSD, take a part, how to open - YouTube
My upgraded T520. Including a spare M.2 mounted on...the ultrabay, a new battery, and a quad i7 (originally a dual i5) Running a retro themed Q4OS. : r/thinkpad