The sinker tubes are made from high quality HDPE100 and are filled with steel wires. The sinker tubes give a more stable volume of the cage nets, even with strong currents and bad weather. The meshes are more open and this provides a better water flow. This together results in a better health of the fish with less stress and cuts. Our cages are all available with sinker tubes and can carry a sinker tube up to 70kg/mtr.