1) 20D spandex is covered by 40D/24F nylon Dty, 2) Available for underwear, knitting fabric - more info check here: https://www.textile-product.com/Spandex-Covered-Yarn-10144824/
Quick Brief
Type: Spandex YarnMaterial: Spandex / NylonPattern: RawStyle: Covered YarnTechnics: Ring SpunUse: Knitting, WeavingTwist: 450TPMPlace of Origin: Shandong China (Mainland)Model Number: 20/40