This is the material Dodge uses for its dashboards.  We carry this in the older EZ-Pass, pre 2012 square style transponder as well as the newer I-Pass, post 2012 round shaped transponder. 

These cases are for the following states: DE, IL, IN, KY, ME, MD, MA, NH, NJ, NY, NC, OH, PA, RI, VA, WV.

Our cases attach to the EZ-Pass and I-Pass using two straps the hook and loop Velcro ends.  As you can see from the second picture, the straps do not interfere with the transponders other Velcro strips that allow the transponder to attach to the windshield.  They are designed not to interfere with the signal to the reader above the toll road.  They also resist fading in direct sunlight.

This is available for sale for both the EZ-Pass and I-Pass.