The Head shapes are different and need a different rubber to seal them correctly. Priming ensures that ink is flowing all the way through the printhead nozzles. HP AMP 125 / HP Deskjet 2600 / 2620 / 2622 / 2630 / 2632 / 2633 / 2634 / 3720 / 3730 / 3732 / 3733 All-in-One / 3735 / 3750 / 3760 / 3762 / 5010 / 5020 / 5030 / 5032.
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