Third-party logistics (3PL) providers offer outsourced logistics services to companies, including inventory management, shipping, and contract management. They allow small-to-medium businesses to leverage an external company's operational capabilities while maintaining some control. Fourth-party logistics (4PL) providers take this a step further by managing resources, technology, and other 3PLs to design and implement comprehensive supply chain solutions, typically for medium-to-large companies. Reverse logistics involves the reuse, remanufacturing, or proper disposal of products and materials, and includes the processes of moving and managing returned or surplus goods.