You will enjoy the bkt was designed to straighten eliminate frizz even in humid weather and leave your hair effortlessly manageable with a lustrous shine i use a product that is formaldehyde free you can rinse it out after 1 hour so no 72 hrs wait it comes in two strengths it lasts 3 4 months it is suitable for any hair type and works particularly well on colour treated hair if you do colour your hair it is best to do it just before you have the bkt a sodium chloride fre