Covered silk yarn
https://www.dongnanfangzhi.com/product/covered-silk-yarn.html
Covered silk yarn
Hangzhou Southeast Textile Co., Ltd.
Bullion cord

Bullion cord:a new structure of yarn, which uses filament or short fiber as the core, and wraps another filament or short fiber sliver. Features: even, fluffy, not easy to break, smooth with less hairiness, high strength.
Application: Bullion cord can be spun by both thick and thin yarns, most of which are stretch yarns, suitable for sports tights, such as swimming suits, ski suits, and female underwear, etc.