CAM2 DEF is a high purity 32.5% (by weight) aqueous urea solution (urea in de-ionized water) developed for use in all SCR (Selective Catalytic Reduction) Emission Control Systems. DEF is a reducing agent which is injected into the hot exhaust gas stream downstream of the diesel particulate filter. It vaporizes in the hot exhaust gas to form ammonia and carbon dioxide which then reacts with the SCR system catalytic converter and the NOx (oxides of nitrogen) in the exhaust, converting the harmful NOx emissions to harmless nitrogen and water. DEF meets ISO 22241-2 specifications and meets all applicable standards and specifications for use in all SCR systems.