Original apple MacBook Pro 4gb ram (2x2gb) from early 2011 MacBook Pro | eBay
CMS 4GB (2x2GB) DDR3 12800 1600MHz Non ECC DIMM Memory Ram Upgrade Compatible with HP/Compaq® Compaq Pro 6305 Small Form Factor Business PC - A82 at Amazon.com
4GB [2x2GB] DDR3-1333 (PC3-10600) RAM Memory Upgrade Kit for the Dell Vostro 230 (Genuine A-Tech Brand) at Amazon.com