https://vnpolyfiber.com/product/virgin-hcs-7d-64mm-virgin-hcs-15d-64mm/
Virgin HCS 7D 64mm, Virgin HCS 15D 64mm - Polyester Staple Fiber Partners from Asia - VNPOLYFIBER
Hollow fibers, characterized by their internal channels (single or multiple holes) and typical crimped shape, are available in untreated ("dry") or
polyester staple fiber