Fluorescent brightener FP 127 (Fluorescent Brightener 378; Optical Brightener FP-127) is a fluorescent brightener. Its small consumption can bring a very good whitening result. Has good compatibility with plastic, good resistance to high temperatures and excellent light fastness and weathering resistance. Fluorescent brightener FP 127 (FBA 378) is especially suitable for brightening serial products of polyvinyl chloride and polystyrene. It can be used in other hot plasticity plastics as well as synthetic fibers, etc.