The first set of cartridges they sent me didn't work at all on our HP7740 - the printer didn't recognize them. The company sent me a set of replacement cartridges. They were accepted by the printer, but the print quality was poor - medium gray instead of black. The company's customer service was responsive and accommodating - they refunded my money fairly quickly after the 2nd set didn't work. So respect to the company, but bang cartridges.
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