SCACs are a requirement for those transacting business with U.S. Government agencies and commercial transporters of petroleum products and forest products among others. Others required to have the code are those that supply retail businesses. It is a unique code usually two-to-four-letter. Carries using Uniform Intermodal Interchange Agreement (UIIA) are also required to have a valid SCAC code. In the petroleum industry the SCAC code is used in their integrated computer software to accelerate the movement of bills of lading, product transfer orders, pipeline tickets and inventory data. Majority of the commercial shippers use the SCAC code in their payment systems and freight bill audit.