Goldwell StyleSign Smoothing Serum Spray instantly transforms hair into a silky, sleek finish while offering powerful protection against heat, frizz, and humidity. Designed to ease the glide of flat irons, this lightweight serum spray delivers long-lasting smoothness and straight styles—without compromising hair health. Formulated to shield strands from heat damage up to 230°C / 446°F, it helps prevent breakage and flyaways while enhancing shine and manageability.