The HP Laserjet M607dn Printer (K0Q15A) supports automatic two-sided (duplex) printing that the HP Laserjet M607n Printer (K0Q14A) does not.REDEFINE BUSINESS EXPECTATIONS – Print consistently high-quality, 2-sided documents with the HP LaserJet Enterprise M607dn, a monochrome duplex laser printer designed to combine performance, energy efficiency, and securityTHE WORLD'S MOST SECURE PRINTING – Your laser printer has the industry's strongest security, with over 175 embedded security features that continually detect and stop attacksSELF-REPAIR FROM HACKS – With HP Sure Start, each printer regularly checks its operating code and repairs itself from attempted hacksCENTRALIZE PRINTING CONTROL – Help build business efficiency with HP Web JetAdmin by easily adding new devices and solutions, updating features, and applying corporate policiesTOP QUALITY AND SPEED – Keep your business moving and productive with a 650-sheet total input tray capacity, a 2.7" LCD control panel, and print speeds of up to 55 pages per minute with this black and white laser printer2-SIDED PRINTS AT THE SPEED OF 1 – Speed through tasks while saving paper—this monochrome laser printer prints 2-sided documents nearly as fast as single-sidedKEEP ENERGY USE DOWN – This black and white duplex laser printer uses exceptionally low amounts of energy, thanks to its innovative design and toner technology