4Gb Ram Memory Dell Dimension E520 E520N E521 E521N Could be Samsung, Kingston, Hynix, Smart, Corsair, Elpida, Micron, or Nanya Warranty: LIFETIME WARRANTY WorldWide Shipping to most countries & USA Capacity: 4gb (4x1gb) - You receive 4 Stick of the 1gb LONG DIMMS for a total of 4gb