Lexmark Return Program Cartridges are sold at a discount versus the prices of regular cartridges in exchange for the customerÈÃ�s agreement to use the cartridge only once & return it only to Lexmark for remanufacturing or recycling. Regular cartridges without this license/agreement sold at regular prices are also available. Regular cartridges are also recyclable at no cost through Lexmark Cartridge Collection Program. Lexmark X644e & X646e MFP supplies are designed for the highest quality output. The supplies are designed for easy customer installation & quality performance