128MB 100 pin SDRAM DIMM for HP.Third Party Equivalent to HP Part Numbers:C9121A Q9121A Q7709A Q7709AX.BEWARE! DO NOT BUY FROM OTHER VENDORS WHO CLAIM THEY ARE SELLING PARTS-QUICKBRAND. OUR WARRANTY IS ONLY FOR ITEMS PURCHASED DIRECTLY FROM PARTS-QUICK. ALLPRODUCTS BRANDED AS PARTS-QUICK ARE TO BE SOLD SOLELY BY PARTS-QUICK. PARTS-QUICK DOESNOT AUTHORIZE THE USE OF IT"S BRANDED PRODUCTS TO OTHER SELLERS. Compatible with:HP Color Laser Jet 2550, 2550L, 2550Ln, 2550n, 2820, 2840.