The upper stem is a solid piece of strong metal with threads that screw into the operating nut.  Most hydrants because of their different shape have different types of upper stems.  The upper stem is connected to the operating nut and to the lower stem.  The two stems are usually linked together with a safety coupling.  

Stem guides (not shown) are required to prevent lower stems from bending. 

Contact us today to have our qualified technicians inspect your hydrant to see if it is in good operating condition.