Fast service and good price.I use OKI C5100 since 2003 and have no problem yet. Toners works fine with this printer.What I expected in every way; perfectly satisfied with the purchase!These cartridges are hard to find at a GREAT PRICE.I have used nothing but genuine Okidata toner cartridges and have never had an issue with quality or performance. I will continue to use the same cartridges as long as the printer continues to work. It is over 6 years old.This Okidata C 5150 printer is the best laserjet I have ever owned. Dependable, versatile, user friendly, very well made and beautiful copies.Also very good customer service tech help.Box was old and yellowed and beat up. I will find out when i use it if it is any good, but have to wait till the present one runs out. by then it will probably be too late for a refund if it is badGenuine OKI 5,000 copy toner cartridge. Works well. Have known people who have had problems when they used generic cartridges rather than genuine OKI cartridges.