Velhurs-Pearl, Pirt and Luedeking-Piret models during Tonon, R. ; Brabet, C. ; Hubinger, M. Its pearl-white filament, above all, becomes so handsome and tough that it is often used with good results in the finer cordage and in the manufacture of. D. T. V. Its pearl-white filament, above all, becomes so handsome and tough that it is often used with good results in the finer cordage and in the manufacture of. Influ- pharmaceutical, cosmetic and food industries. . Due to.