Steel-based butterfly valves feature a mechanical seal construction. At the shaft head are the flow direction arrow and switch positioning device. Depending on the needs of the user, a customised butterfly valve is also offered. Along with the valve, the appropriate mounting bolts and nuts will be provided. Under 0.5Mpa for 5 minutes, there is less than 10 grammes of oil leakage. According to the needs of the customers, customised butterfly valves with specified specifications and materials are also available.