VICTORSTAR @ Remanufactured Ink Cartridges for HP 934XL (Black) + 935XL (C,Y,M) High Yield for HP OfficeJet Pro 6830 6820 6230 OfficeJet 6812 6815 6835 Printer with New Generation Chips All empty cartridges are bought from the professional recycling dealers, each empty cartridge will be tested before stroage to assure the quality Use the advanced cleaning equipments with ion-free water to clean the empties to assure all products with same high quality Use the automatic vacuum injectors to assure the quality stable, each product should be tested on printers Ink volume is equal or more than the original volume, ink is done several strict testing and experiment before use Qualified products should pass the environmental test, they can be shipped by air, land or sea with leafless