Polyvinylidene fluoride (PVDF) is an insulating material for cables with the DIN/VDE designation 10Y. Polyvinylidene fluoride is an organic ferroelectric that can be used as a ferromagnetic polymer for memory elements. It also has piezoelectric properties and is used for the diaphragms of midrange speakers. Polyvinylidene fluoride is used as a dielectric in film capacitors. The dielectric constant of polyvinylidene fluoride is between 18 and 50.