1 Plug and valve body (F4 lining) with an ideal taper design, when cannot be sealed while in use due to wear, can be adjusted by adjusting the valve cover screws move the plug down and compensation in the sealing surface of the sealing force. 

2 sealing components the second outer seal, in the case of seal failures, preventing media from stem to leak outside. 

3 after the four bolts on the bonnet is open, you can remove all parts of the valve, direct replacement of the valve components without the need to remove the valve from the pipeline. 

4 with the import and export side and sealing advantages throughout the working process of sealing surfaces low friction, flexible operation, does not require lubrication.