Added to the doors and rear hatch of my 4Runner and it's really helped reduce cabin noise and improve the sound quality of the speakers. Doors feel more solid when they close. Less interior rattles. Highly recommend. Apply it in large sheets to outer door skins, the inner door skins, AND the inside of the plastic door panels for best effects. The NVX sound deadening products have tested the best of all of the more budget-friendly brands. Apparently the CLD butyl layer on this is the same as their standard CLD sheets.