Delivering up to two weeks of flyaway control, the L'Oréal Professionnel Keratin Alpha Sleek Hair Serum encourages glass-like shine and ultra-sleek results. The leave-in treatment helps to protect against the effects of humidity and thermal damage up to 230°C. A 5% Keratin Sealer complex encourages a fuller, healthier look, while promising up to five days of mirror-shine and smoothness. Saturate strands with the lightweight, heat-activated spray and blow dry, then flat iron for optimal results.