In summary, the key to determining the suitability of a material to a given application is its response to applied stress. In typical applications, screws and clips induce stress on Gap Pad materials. The moment of assembly is the point at which the material will experience the highest levels of physical stress. An important characteristic of any Gap Pad material is its long-term ability to deflect this stress at low pressures. An important characteristic of a gap filling product is its ability to deflect at low pressures. This property is reflected in compressive modulus (Young’s Modulus) and compression deflection data. Modulus is a measure of the hardness or softness of a material and is equal to stress divided by strain. Stress is equal to pressure. Strain or deflection is equal to the ratio of the change in thickness to the original thickness of the material. The lower the modulus the softer the material. In most cases, a soft gap filling material is desired to minimize the pressure exerted on printed circuit boards, component leads, and solder joints while the material is being deflected during the assembly process.