Fluorescent whitening agent OB-1 is yellow crystal, insoluble in water, odorless, stable performance, the maximum absorption wavelength of 374nm, with a strong fluorescence, emission wavelength of 434nm. Product Description Optical brightener OB-1 specification: Item Specification Name Optical brightener OB-1 Class Whitening agent Appearance Yellow powder Application Suitable for polyester and plastic Fineness 300mesh z