You are buying the genuine replacement center stem that you seen the photographs. These are often referred to as basket stems, circulator pump stems, or even stem assemblies. Whatever you want to call it, this is the part that goes right in the middle of your percolator.  Genuine piece from a vintage Farberware percolator, but it should fit virtually all 8 cup percolators by Farberware, both older and newer. The total length is about 7.5".

 

SEE PICTURES! SUPER CLEAN!