4GB Memory for Lenovo ThinkCentre M73 SFF Small Form Factor DDR3 PC3-12800 Desktop DIMM RAM (PARTS-QUICK Brand) at Amazon.com
Amazon.com: lenovo ThinkCentre M73 SFF Small Form Factor Business Desktop Computer, Intel Dual-Core i3-4130 3.4GHz, 8GB RAM, 500GB HDD, USB 3.0, WiFi, DVD, Windows 10 Professional (Renewed) : Electronics