If your ok trying them
Crutchfield Customer Review (What's this?)
Bought them to create more low end in my new JBL 6 3/4 inch speakers for my 2005 Corolla. Simply, they were too big and interfered with the window. Had to completely cut the back off and was left with an inch or so of the foam circling the back of the speaker. Easy to work with, decent quality foam.
Pros: easy to work with, good quality foam
Cons: too big for application, desired "bass" effect non-existent due to modification.