The toner cartridges that fall under Lexmark's return program are printing toners sold at a reduced price, on the condition that the customer agrees that the cartridges will be used only once and returned only to Lexmark for remanufacturing or recycling. These single-use toners cease to function when they reach the end of their designated lifespan, as determined by Lexmark (a variable amount of toner may remain in the cartridges when replacement is required). These toners can also automatically update the printer's memory to protect it from non-genuine and unauthorized products.