A list of all VDECS for all types of diesel engines (i.e., on-road, off-road, stationary, etc.) is available on our Verification website: http://www.arb.ca.gov/diesel/verdev/vt/cvt.htm. The website also contains specific information and requirements for each VDECS, based on the level of diesel PM emission control: Level 3 is at least 85 percent reduction; Level 2 is at least 50 percent reduction; and Level 1 is at least 25 percent reduction. It is important to confirm the VDECS that are available for your specific engine and application before making any purchasing decisions. Please remember that if retrofitting in order to comply with the regulation, the highest level available VDECS must be installed. 21.