These frames are 4-1/4"” thick and mount to the back side of your wall kit to fill the gap between the wall kit and the sheet metal of the van. The frame comes in three pieces 2x 2” foam and a 1"/4” Baltic Birch ring. The Baltic Birch ring gives the frame structure and provides for a solid mounting surface to attach to the wall kit. We recommend using 3M Foam Fast 74 to construct and add finishing material to the frame. These frames can be finished to match your wall kit for a seamless look or used to accent with a fun color or pattern.