Female thread ball joint assemblies feature female thread coming out of the bottom of the assembly and an open spherical ball bearing. The bearing raceway is locked in place by a groove-trunnion design made of fiber reinforced nylon, the spherical ball is made from case hardened low carbon steel, and the housing is made from low carbon steel. The whole assembly is zinc plated and dichromate treated for corrosion resistance. Most sizes are avaliable in both right and left hand thread. Ball joint assemblies are also known as "heim" joints or rod ends.