Nioxin Density Defend Strong Hold Hairspray is an aerosol finishing spray that adds firm hold and a fuller-looking effect for all hair types. It is applied to damp hair before blow-drying, so it works into the style from the roots rather than only being sprayed on at the end, helping support the appearance of volume as hair dries. The aerosol mist is designed to hold a style without a stiff, over-sprayed feel and to comb out easily when it is time to restyle.