As a vital part of your Lexmark laser printer's assembly, the imaging unit needs to be in top condition. Use this genuine Lexmark replacement unit to refresh your printer after extended use. It uses an electrostatic charge to assist the application of black toner to the page, so a brand new imaging unit ensures crisp text and images as soon as you install it. This unit is designed for C540 and X543 series printers, and features a 30,000 page lifespan.