128MB STICK For HP-Compaq DesignJet Series 500 500 Plus 500PS 800 800PS. SO-DIMM SD NON-ECC PC100 100MHz RAM Memory. Genuine A-Tech Brand. 128MB STICK SO-DIMM SD NON-ECC PC100 100MHz RAM Memory Genuine A-Tech Memory Lifetime Warranty Toll Free Technical Support 1-866-557-4527 Designed For HP-Compaq DesignJet Series. (See Compatibility List Below)