The valve stem and sealing surfaces are completely protected from dirt and corrosion by the stemcap, whether the valve is in an open or closed position.
不管是在阀门开启位置，还是关闭位置，阀杆和密封面有阀杆盖帽的保护，能防止污物入内，防止腐蚀。
2
It is a special kind of stem cells with highly proliferative and self-regenerative cap ability to maintain its number stable and generate tumor.
It is composed of a taper shank cap, a hollow taper shank, an awl perch, an awl stem casing, a permanent magnet and screwdriver heads of different format dimensions.