Collagen Extensions These extensions are made with collagen as the main material. They are not human hair, but also not fiber; they are artificial hair. Color: Black BK01 Length: 100cm Weight: 114g (including the bag) I purchased several, and I am selling this one as I didn't use it. The bag is slightly damaged, but the product is unused. My personal experience using them is that they were very easy to manage. These extensions curl more easily than human hair, and the curls last longer. They curl at low temperatures, so the hair quality lasts longer. When using an iron, use a low temperature. High temperatures will damage the hair. It is recommended to mix them with human hair, as this improves the hold and curl retention. You can use them not only as a single product but also mixed with other hair. The appearance may be somewhat similar to fiber, but unlike fiber, they are not difficult to curl or have a flimsy feel. The curls hold very well and don't come out easily. Some people with beautiful hair found them easier to blend in and use than human hair. The recommendation is to mix them with human hair, which allows them to blend in with the texture of human hair, and the collagen enhances the curl and the beauty of the hair quality. *Please read the profile and purchase only if you agree with the terms. Color: Black Wig Length: Long