Lexmark MS431dn Single Function Mono. Light, compact, and fast, the MS431dn supports output up to 42 pages per minute*. Available Extra High Yield Unison™ toner offers up to 20,000 pages of output**, while an optional 550-sheet tray supports longer print runs. A 1-GHz multi-core processor powers through big jobs, and Lexmark full-spectrum security helps protect sensitive information.