1GB KIT (2 x 512MB) For Dell Inspiron Notebook Series 4100. SO-DIMM SD NON-ECC PC133 133MHz RAM Memory. Genuine A-Tech Brand. 1GB KIT (2 x 512MB) SO-DIMM SD NON-ECC PC133 133MHz RAM Memory Genuine A-Tech Memory Lifetime Warranty Toll Free Technical Support 1-866-557-4527 Designed For Dell Inspiron Notebook Series. (See Compatibility List Below)