A "VOLLEYBALL NET 2.5MM (GTO)" refers to a specific model of volleyball net, likely the GTO DX 10 Mesh, that has a net twine thickness of 2.5mm and is made by the brand GTO. These nets are constructed from twisted PE (polyethylene) and typically include a steel cable and a PVC canvas headband for durability. They are suitable for various levels of play and can be used outdoors.