Extensions Valve is one of the most common valves mainly used to connect or disconnect the line of media; especially suitable for medium and large diameter pipe. Plus pole soft sealing valve stem to drive the gate of the lift gate stem drive along the stem transmission thread in the external body, therefore, can visually determine the shutter open and close depending on the direction of the movement and position of the valve stem and location, and ease of transmission thread lubrication and corrosion from the fluid, but it requires a larger installation space. Features: stem extension, convenient location for high operating position; channel flow, flow coefficient is small; the sealing reliable, flexible operation