6.5" Door Speaker Foam Ring (Pair) A high-quality speaker foam ring can greatly improve bass dramatically in the doors. After testing we found that it can make the overall frequency response smoother and reduce unwanted rear reflections. This is the quickest and simplest solution for enhancing midbass. These 6.5 Inch Speaker baffle foam rings are the most cost effective upgrade and simple upgrade you can make to your car sound today. It's affordable and extremely easy to install.