2GB KIT (2 x 1GB) For HP-Compaq Pavilion 500 Series 503g 503k 503n 503w 503x 504n 505n 505w 512a 512c 512d 513 513a 513c 513d 513g 513m 513n 513t 513w 513x 514x 515 515n 515x 522a 522c 522n 523a 523k 523n 524w 530k 530n 530t 532n 532w 533a 533c 540n 542x 543x 544a 544n 545x-b 551w 551w-b 552 552w 552x 553w 553x 554e 554x-b 555e 555y 560w 563 563w 564a 564w 576x-b. DIMM DDR NON-ECC PC2100 266MHz RAM Memory. Genuine A-Tech Brand. 2GB KIT (2 x 1GB) DIMM DDR NON-ECC PC2100 266MHz RAM Memory Genuine A-Tech Memory Lifetime Warranty Toll Free Technical Support 1-866-557-4527 Designed For HP-Compaq Pavilion 500 Series. (See Compatibility List Below)