... rectangular or round ducts.exhaust valve. Supply and exhaust valve is designed for use in entertainment and industrial areas. They are also ... rectangular or round ducts.Sizes available: 100, 125, 150 and 200 mm in diameter. Zhaoqing Grandaire Air conditioning Co.,Ltd ... each year, including USA, UK, Australia, Belgium, Spain, Israel and other countries.We are looking forword to estabalish long-term ...