QQ:2277-0811-45.3600-5978.136-6223-0127.139-2373-4073 

Memory 
Option # Manufacturing
Part # Description Previous
Part # 
SE6X2A11Z  4GB Memory Expansion (2 × 2GB) X-Option,  
371-4656  2GB DDR3-1333/PC3-10600 DIMM,  n/a 
SE6X2B11Z  8GB Memory Expansion (2 × 4GB) X-Option,  
371-4872  4GB DDR3-1333/PC3-10600 DIMM,  n/a 
SE6X2C11Z  16GB Memory Expansion (2 × 8GB) X-Option,  
371-4658  8GB DDR3-1333/PC3-10600 DIMM,  n