What is a Thermal Gap Pad? Thermal Gap Pads are gaskets that have a broad offering of different thicknesses, are typically low closure force in nature, electrically isolating and, of course, thermally conductive. The goal of this product is to fill air gaps with a soft and compliant material having much better thermal transfer properties than that of air. A typical use would be to heat sink a PC board to the metal box it resides in via the Thermal Gap Pad.