The ability of the cushioning structure to deflect at the surface and to conform to body shape, preventing a concentration of pressure on the body. Compression Modulus - Ratio of an FPF's ability to support force at different indentation (or compression) levels. It is determined by taking the ratio of the FPF's IFD at 25% indentation and 65% indentation (65% IFD/25% IFD). The compression modulus is typically a function of FPF chemical formulation and the manufacturing process. IN most cases, the higher the density the greater the compression modulus. Other terms that are used interchangeably are: support factor, and modulus.