A-TECH 4GB STICK For ASUS ASmobile X Series Notebook X42 X42Jr X52 X52JK X53E X53SC X53TA X53U X54H X54HR X54HY X54L. SO-DIMM DDR3 NON-ECC PC3-10600 1333MHz RAM Memory. Genuine Brand. 4GB STICK SO-DIMM DDR3 NON-ECC PC3-10600 1333MHz RAM Memory Genuine A-Tech Memory Lifetime Warranty Toll Free Technical Support 1-866-557-4527 Designed For ASUS ASmobile X Series Notebook. (See Compatibility List Below)