The companies we carry (with the exception of a few "high fashion" brands) specialize in making medical-grade hair for women recovering from not only hair loss but illness as well. They take into careful consideration any sensitivities or immunity issues their clients may have along with providing high-end cap features for comfort. Medical wigs tend to have comfort features and high-end finishes. These include felt, silicone, or polyurethane in the caps to aid with grip and comfort when worn against a bare scalp. If they have lace, the lace is precut. All of the non-heat-friendly synthetic hair in our store is virtually the same, with only minor variations. It is ALL kanekalon modacrylic (petroleum-based) fiber that has been treated with silicates and other chemical agents for static and flame-retardancy.\nEach company has its own proprietary blend of what they put into the hair and they keep it a trademarked, patented, tight-lipped secret.\nOur manufacturers do not provide us with detailed information on what is used to process their synthetic fibers. For a more in-depth response on a certain manufacturer's proprietary fiber treatment blend, I recommend reaching out to them directly.\n\nThis is an excerpt from our CysterWigs Knowledge Base. Check it out on our private site to see over 500 articles all about our store, wigs, and how to wear the hair!