The twelfth US Customs and Border Protection P-3 Orion to undergo Mid-Life Upgrade, or MLU, program modifications at the Lockheed Martin facility in Greenville, South Carolina, was re-delivered on 18 March 2015. The deliver came thirty-seven days ahead of schedule. A total of fourteen Customs P-3s are scheduled to receive the MLU modifications. The MLU replaces the outer wings, center wing, horizontal stabilizer and horizontal stabilizer leading edges. All necessary fatigue life-limiting structures are replaced, leading to significantly reduced maintenance and sustainment costs. The MLU will enable operators to fly the P-3 twenty-to-twenty-five more years. While receiving the new wings, the aircraft also undergo phased depot maintenance.