OEM stands for Original Equipment Manfacturer. Compatible means it works in the same machines but is manufactured by someone other than the OEM. Both OEM and Compatible cartridges contain recycled materials. All Compatible cartridges are not remanufactured the same way. The Concord Premium series cartridges are manufactured from carefully selected partners that are all ISO 9000 certified as well as being STMC certified guaranteeing consistently high quality cartridges. We offer a Lifetime warranty and allow new customers 30 days to use the product before asking for payment. Using compatible cartridges saves money and has a positive effect on the environment. An educated consumer is our best customer.