ClearSign Combustion Corporation announced the completion, customer acceptance and issuance of payment for the final phase of a multiphase project. This project successfully retrofitted Duplex technology into enclosed ground flares for a major California oil producer. This contract was previously announced, and was ordered through Advanced Combustion and Process Controls, the oil producer's prime contractor and ClearSign's representative in Southern California. The results of the testing were independently confirmed by the customer and Advanced Combustion and Process Controls. This project consisted of retrofitting multiple units, including larger capacity units, and brought them in line with requested performance characteristics.