Rolls-Royce Holdings Plc designs, develops, manufactures, and services integrated power systems for use in the air, on land, and at sea. The firm's segments include Civil Aerospace, Defense, Power Systems, and New Markets. The Civil Aerospace segment is engaged in the development, manufacture, marketing and sales of commercial aero engines and aftermarket services. The Defense segment is engaged in the development, manufacture, marketing and sales of military aero engines, naval engines, submarine nuclear power plants and aftermarket services. The Power Systems segment is engaged in the development, manufacture, marketing, and sales of integrated solutions for onsite power and propulsion. The New Markets segment is engaged in the development, manufacture, and sales of small modular reactors (SMR) and new electrical power solutions. Its subsidiaries include Aerospace Transmission Technologies GmbH and PT Rolls-Royce, among others.