... Product Description The main product is hi-performance bare spandex yarn, 15D,20D,30D,40D,70D,105D,140D,210D,280D,420D ... produce white and black spandex. Usage: Covering core, air interlacing yarn, circularly knitting, warp knitting, weft knitting, stockings, covering with cotton ... two kinds of segments.Due to the polymer chain is formed by soft segments and hard segments. Ruyi spandex can be ...