From Bra Maker's Supply:
The fabric is strong and supportive and is a reversible fabric (shiny finish on one side – matte finish on the other). You choose which side to use, according to the look you desire.
Width: 58″-60″ (147-150 cm)
Stretch: very little mechanical give, 5%-7% in the lengthwise direction
Finish: reversible – shiny face, matte back
Content: 100% polyester
Uses: bra cups