The Start-Stop mode of operation means that the refrigeration unit starts and stops based on preset criteria. The Start-Stop operation is based on thermostat setpoint and the return air temperature. It allows the reefer unit direct drive engine to shut down when return air temperature has reached setpoint. Because the engine is not consuming fuel or accumulating engine hours, it is saving energy and money. However, Start-Stop is not universally recommended for all perishable cargoes. The Start-Stop setting can be used with selected frozen cargoes, but it should not be utilized for fresh produce and other temperature sensitive cargoes.