What are OEM and Compatible Cartridges?
Compatible or remanufactured toner cartridge offers more recycled parts than an OEM cartridge. They can be all new compatible parts made by a third party manufacturer or by recycled virgin OEM core [used once] saves plastic in the nationwide landfills. They could be rebuilt with new components, then tested and sent back for re-used again. These cartridges may have different components and ink toners than OEM due to patents. However, compatible/remanufactured would have similar quality to an OEM cartridge if not greater and can offer higher yield up to double the OEM cartridge.
OEM Cartridge: What this means is that the cartridge was made or licensed by the Original Equipment Manufacturer. If you own a HP laser jet printer for instance, then the HP brand is the OEM cartridge. It may be made from both new and recycled components. That's what the return label there for.