Toner Refill Store's premium compatible Okidata black toner cartridges contain brand new parts and are 100% guaranteed to meet or exceed your expectations and surpass the print quality of the OEM (Original Equipment Manufacturer) Okidata DOC-IT 4000. Our Okidata DOC-IT 4000 monochrome toner cartridges are made from the highest quality materials and are manufactured in an ISO-9001 certified factory. We also carry numerous toner refill kits which allow you to go green and SAVE! Toner Refill Store supplies each cartridge with a brand new smart chip which will get rid of your 'low toner' message. The use of our premium compatible laser toner cartridges for the Okidata DOC-IT 4000 does not void your printer's warranty. Our Okidata DOC-IT 4000 high yield laser toner cartridges have a 'One Year 100% Satisfaction Guarantee'.