BOS Replacement Toner Cartridge, Samsung MLTD203L, for use in: M3320, 3370, 3820, 3870, 4020, 4070 Series, Black, 5,000PY Quality Control Our Full Product Line is Supported High Quality Cartridges Warranty All steps in the manufacturing process are scrutinized. From the manufacturing components coming in, to the final cartridge being shipped out of our facility, all are subject to a visual inspection, pre-testing, post testing and then bar coding.Our US Based technical team is available to help you with any Questions or concerns that you have. Our team is available to assist you Monday through Friday at (888)570-1986Our Technicians work in groups of 5 employees. Each technician is responsible for the building of each cartridge from the break down process to the re-manufacture and post test. Every Cartridge can be traced back to who produced it. All toner cartridges are tested 100% prior to leaving our facility. We will replace any defective product for up to 12 months from date of purchase. We guarantee that our cartridges will not cause damage, printer wear or deterioration. We will cover the cost of repair or fair market replacement of the printer, with proper documentation If damage occurs.