Thermal Hair is made from polypropylene fiber that changes color in reaction to changes in temperature.
Thermal Hair has a higher resistance to heat than kanekalon, but can still be sealed with a steamer and will melt under high, dry heat like a straightener/flat iron. It will not shrink when sealed, but will hold its shape once set.
If the ambient temperature of the room you're in is close to the point where the color changes, sometimes it will appear to get "stuck." For example, your hair might be purple in the bag, turn teal from the warmth of your hands when you remove it, then stay teal after you've set it down. You can get it to go back to purple by exposing it to a much colder temperature, like an ice pack.
Thermal Hair cannot "burn out" - the fiber will never stop being able to change colors.
Length: 19" (48 cm) folded, 38" (96 cm) unfolded.
Weight: 0.88 oz (25 g). Thermal hair comes in small packs that contain enough for a few braids, or for highlights/accents.
This color switches between medium blue and blond. The "warm" color is the blond, so if it's blue and you want to change it, apply heat (like the heating pad in the video). If it's blond and you want to change it, expose it to the cold (like the ice pack in the video).