Shut-off valve requires a lower leakage as possible, the leakage of soft-sealed valve is the lowest, of course, cut off the effect, but not wear-resistant, poor reliability. From the leakage is small, sealed and reliable double standards, the soft seal cut off as good as the hard seal cut off. Such as full-function ultra-light control valve, sealed and piled with wear-resistant alloy protection, high reliability, leakage rate of 10-7, has been able to meet the requirements of shut-off valve.