On the exhaust of the Cummins 6.7-liter Turbo Diesel option in Ram heavy-duty pickups, a diesel particulate filter and an adsorber catalyst to reduce oxides of nitrogen (NOx) satisfy EPA’s 2010 on-road diesel emissions limits. This system, which does not require diesel emission fluid (DEF), makes the Ram/Cummins pairing a simpler choice for diesel work-truck buyers. Cab choices are Regular, Quad and Crew.