The Manfrotto 047-2 Alucore has many uses but it is most often used as a cross bar to support backdrops, lighting, and even cameras. This product comes in two 4.5 ft. sections joined with an expanding Alu-connector. Light weight and strong, multiple lengths of Alucore can be joined with additional Alu-connectors. It allows you to use the Expan background support system with un-cored seamless paper or cloth backgrounds