DetailsHeat Seal by Paul Mitchell is a humidity resistant styling spray to protect the hair from heat stylers including hair dryers, straightening irons and curling tongs. Heat Seal by Paul Mitchell adds extra volume to the hair as well as giving the hair a vibrant shine, It also controls frizz. Your hair style lasts all day when using Heat Seal. Apply to towel dried hair and comb through, style as normal. Heat seal activates with heat.