This integrating sphere contains an integrated light source and is designed for the measurement of diffuse reflectance when used with a fiber optic spectrometer. It uses “d/8” geometry, which is required for reflectance measurement of diffuse surfaces, especially when spectral reflectance is used for the color measurement of materials. It is machined from PTFE which is highly reflective (>97%) over a broad spectral range of 350 to > 2600nm.