General medium and low pressure cut-off valve is low and high, cut off when the filler does not force, reduce the probability of leakage, can extend the service life.
General >DNA100 cut-off valve can be used to high and low; large-caliber and high-pressure state to close the valve when using low and high, it is more difficult, and second, because if high-pressure and large-diameter state with low-elevation, the stem is subject to long-term water pressure bend easily deformed, the influence of the valve 's safety and containment; is the choice of three high-low, then the diameter of the stem can be dots, also for the manufacturers and users for cost savings point.