I am a mobile Notary Public and found this website doing a Google search for toner. This website has saved me soooo much money. I go through quite a bit of toner and these cartridges work excellent. I do get around 5000 copies per cartridge and the best part is when you buy two cartridges, they send you one for free! I have not had any issues with compatibility in either my Samsung printer nor my HP. I would definitely recommend this to anyone looking for value.