4 PCS Car 6.5" Speaker Voice Coil, Slow Rebound Sealed Speaker Circle to Avoid Sound Diffusion, Improve Speaker Sound Effect Bass Pad, Universal for Cars Speaker Blockers Accessories (Black)

I haven't put these to use yet, I got these for an upcoming build.The rings are about 1 inch thick. The interior diameter is just a little bit smaller than the exterior of the basket on my Polk 6.5 component set, measures roughly 5.5 inches matching the item description. The Exterior diameter measures roughly 6.75 inches also matching the listing.The foam is very soft and feels like memory foam. Though it is 1 inch thick uncompressed it will compress all the way to about 0.25 inches without any issue.The backing is a 3m adhesive which is tried and true.Comes with the center foam as well, this could be used to help silence vibrations in other bits of the door panel. Or if you have a good way to cut it could be used to make rings for a set of 3.5 speakers too.

This is a great deal on a set of four 6.5" speaker foam rings and corresponding rebound pads. The foam seems to be a closed cell memory foam that is very flexible and squishy, so it seems to depress without contorting into the speaker ring, So, if you have a very tight fit, this would be a good choice as it compresses quite flat if needed. Again, it's basically a memory foam ring. The adhesive backing is a very, very sticky 3M, which is always welcome to see and instills confidence in me that it will hold firm in place. Considering you get four rings and reflection pads, I consider this quite a good value for the set.