Caterpillar offers three versions of each RP Series model generator sold in North America...one for California (CARB), one for the other 49 states in the US (EPA), and one for Canada (CSA certified).  The California Air Resources Board (CARB) compliant models come equipped with special emission reduction technology and have a unique part number and UPC that can be used to identify them as CARB models.  This information is provided on our website as well as via  indications on the carton.  Please be aware that portable generators purchased outside the state of California may not meet California's specific emissions requirements.  Portable generator owners are responsible for ensuring products they bring into California meet state standards and regulations, and are responsible for the costs of any upgrades required to ensure compliance.  These upgrades are not covered under the warranty. 

There is no performance difference between CARB and EPA units. The difference is there is a "vapor canister" (referred above as the special emission reduction technology) that makes the emissions from these units compliant to the California Air Resource Board requirements and thus the unit is more expensive.