8GB Stick 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
Refurbished: ThinkPad Laptop T420 Intel Core i5 2nd Gen 2520M (2.50 GHz) 4 GB Memory 320 GB HDD Intel HD Graphics 3000 14.0" Windows 7 Professional 64-Bit - Newegg.com
Lenovo ThinkPad T420 Details, Specs and Photos
Refurbished LENOVO Thinkpad T420 Laptop B Grade Intel i5 Dual Core Gen 2 8GB RAM 320GB SATA Windows 10 Home 64 Bit - Walmart.com