To determine which foam is the right one, Measure the inside diameter (ID) and outside diameter (OD) of your original foam.
Imagine your speaker is a clock. OD- measure the outside edge of the original foam at 9:00, across the center of the speaker to the other outside edge of the foam at 3:00 (remove gaskets if they block your view). If the foam is completely disintegrated, you can still see a line where it has been. ID, measure the same way from the inside edge of the foam, across the center of the speaker, to the other inside foam edge. Remember the inside edge of the foam must overlap the outside edge of the cone by approximately 1/4″ (0.250). Do not measure the speaker frame or cone. (multiply by 25.4 to convert standard to millimeter)