A compression spring is an open coil helical Spring offering resistance when a load is
       Applied against it.
       1、Open
       2、Open and Ground
       3、Clesed only
       4、Closed and ground

       Mandatory data:
       1、Controlling Diameter
       a、outside Diameter,O.D.
       b、Inside Diameter,I.D.            
       2、Wire size,material,and class
       3、Numbers of active coils
       4、Rotating Direction(Left or Right)
       5、Free Length
       6、Loading
       7、Type of end