. . "2a and 2 b are a top view and a side cut-away view, respectively, of the magnetic ring of the first embodiment; [0017]FIGS. 3a and 3 b are a top view and a side cut-away view, respectively, of the base washer of the first embodiment; [0018]FIGS. 3c and 3 d are a top view and a side cut-away view, respectively, of the first and second base plates of the first embodiment; [0019]FIGS. 4a, 4 b, and 4" . . .