Measure your original foam so you will know which Refoam Kit is right for you. It is important to measure the FOAM only and not the frame or cone. Measure the inside and outside diameter of the original foam. Even if the foam has completely disintegrated, you should still be able to see a line where the adhesives were or where the foam once was.
Imagine your speaker is a clock. You can find the OD (outside diameter of the foam) by measuring from the outside edge of the original foam at 9:00 all the way across the center of the speaker to the other outside edge of the foam at 3:00. To get the ID (inside diameter) do the same thing from the inside edge of the foam across the center (9:00 and 3:00) of the speaker to the other inside edge.
Do not measure the frame. Some speakers have an extra large outside flange on the frame that can cause confusion. Do not measure the cone. If there is a gasket, remove it so you can measure the foam edge under it. When evaluating, remember, the inside edge of the foam will overlap the outside edge of the cone by approximately 1/4″ (0.250).
The FOAM OD + ID vs ROLL OD + ID can be confusing too. See if this helps….. You can click on all images for larger views.
If you need help, send a picture of the speaker and tape measure. Be sure we can see from one outside edge to the other outside edge (9:00-3:00). Tell us the brand and we will respond with our opinion.