Thermally activated, EXO gives stronger, more energized, defined wave, along with all the healthy benefits of the thio-free ISO system. Offers lasting texture as well as unprecedented softness and shine, yet strong enough for luscious curls on long, short or resistant hair. \n \nDesigned for: Energized Curls on Longer and Resistant Hair Normal to Coarse Texture Tinted Hair in Good Condition (20 volume or less) Resistant or Grey Hair Long Hair.