Genuine Lexmark supplies are engineered to work best with your Lexmark printer, delivering print quality from the first page to the last. This imaging unit is designed to work best with Unison toner, a unique formulation which consistently delivers outstanding image quality. The Lexmark Return Programme Imaging Units are patented devices sold at a special price subject to the restriction that the imaging unit may be used only once. The customer agrees to return the imaging unit only to Lexmark for remanufacture and/or recycling. The Return Programme imaging units are designed to stop working when they reach their respective rated life. The imaging units are designed to update the memory automatically in the printer to protect against the introduction of counterfeit and/or unauthorised third party cartridges. Replacement imaging units sold without these terms are also available.