Wintec Value MHzCL9 4GB SODIMM Retail 2Rx8 Upgrade Kit 4 Not a Kit (Single) DDR3 1333 (PC3 10600) 204-Pin SO-DIMM 3VH13339S9-4GRU 4GB DDR3 1333MHz PC10600 SO-DIMM memory module ESD wrist strap Screwdriver Pre-paid return envelope to recycle the old memory module Step-by-step instruction manual and links to DIY videos online