This Imaging Unit is designed to work best with Unison toner in your Lexmark B3340dw, B3442dw, MB3442adw, MB3442i, MS331dn, MS431dn, MS431dw, MX331adn,MX431adn and MX431adw, Essential to Lexmark print system performance, Unison Toner's unique formulation consistently delivers outstanding image quality, ensures long-life print system reliability and promotes superior sustainability - all in an innovative, shake-free print system. Genuine Lexmark supplies are engineered to work Best Together with your Lexmark printer, delivering excellent print quality from the first page to the last. Imaging unit yields approximately 40,000 pages based on 3 average letter/A4-size pages per print job and approximately 5 percent coverage.