These extensions have a length of 60 cm (24") and are attached with heat or ultrasonic like all keratin strands. Individual strands are welded with their own hair. If longer extensions are used, be aware of their number and volume. With normal self-hairs, 100-125 strands are sufficient, with dense or very dense self-hairs approx. 150-225 strands. This type of hair extension has been very popular for many years, as the extensions are attached to the hair by themselves and only after the extensions have been re-groomed does a hairdresser again have to go to remove the hair extensions. Many of our customers rebond the hair and wear it for another 4 months. So maintains you can use this hair 8-12 months. Of course, good care is very important. Everything you need to rebond, extend and maintain the extensions can be found in our shop. If you need assistance with the selection, do not hesitate to contact our customer service.