Each strand has approx 180 individual hairs that are bonded together on the ends by a keratin protein glue shape of Nail shape hair that is melted by a fusion iron or fusion iron or fusion heat wand which connected to individual section of your hair. Since these 100% human sleek hair has been cuticle aligned to ensure less tangling and durability , you can wash, dry and style just like your own hair. You may also curl, flat ironed or even color that hair. It can take anywhere from 150-250 strands for a full head of hair depending on how thick your own hair is. They last approx 3-4 months before they need to take out and redo again.