Cable trays are used typically as raceways for cables and wires. A cable tray system supports and protects both power and signal cables and allows cabling networks to be upgraded, reconfigured, or relocated. Cable tray systems can have several designs, including ladder, solid bottom, channel, trough, wire mesh, and single rail. A metallic cable tray is made of steel or aluminum. A non-metallic cable tray can be made of polyvinyl chloride (PVC) or fiberglass. PVC cable trays are an aluminum cable tray or a steel cable tray with PVC coating. A wire mesh cable tray provides a field-adaptable system for low voltage, telecommunication and fiber optic cables. Use of a cable tray roller can reduce pulling stress on cables, shear load on cable trays, and overall installation time. The amount of cable tray wire that can be installed in a cable tray varies with the type of cable (e.g., twisted pair, coaxial, and fiber optic). Cable tray manufacturers are located across the United States and around the world.