The pad is a specially formulated polyurethane (PU) material that sticks to most surfaces, is reusable and leaves no residue. We picked this material because it is versatile and extremely durable. In our last Capta and Foco projects, we used the same type of PU pad with excellent results. Our PU pad sticks to more surfaces than a suction cup and works in more situations. Refreshing and removing built up debris and dirt from the pad can easily be performed using running water and allowing the pad to air dry. This is not a new technology as similar products exist in the medical industry such as reusable pads used for heart monitoring, physical therapy, etc. It truly is an amazing material. Thanks again for your time and support. Cheers!!