4GB KIT 2x 2GB Gateway SX Series Desktop SX2855-UB10P SX2855-UB22P SX2855-UR20P SX2855-UR21P SX2860-43M SX2860-55 SX2860-CI5-2400 DIMM DDR3 NON-ECC PC3-10600 1333MHz RAM Memory Genuine A-Tech Brand 4GB KIT (2 x 2GB) 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 Gateway SX Series Desktop. (See Compatibility List Below)