In relation to the actual antenna assembly and function, there is no difference between the KA-44B P/N 071-1234-00 and 071-1234-01. When the KA-44B -01 originally shipped New from the factory, it included a grounding ring. This grounding ring can be obtained separately and is only listed in the installation manual. The grounding ring is not part permanently attached to the 071-1234-01 assembly and is not part of the -01 bill of materials.