Optical light-emitting diodes, also known as polymer bulking agents, obtical brightener (OB) and also fluorescent bleaching agents (Aria Add 2161), work through a fluorescence mechanism that absorbs light in the uv spectrum and in The blue region releases the visible spectrum, making it look brighter and more refined. These masterbatches are used to cover the natural yellowing of plastics, the whiteness of the polymeric products, the higher coverage of the white masterbatch (the color of the blue color), the improvement of the initial color and the brightness of the painted parts.