Mettler Poly Sheen 40 Weight Polyester Embroidery Thread, 220 yd, Light Silvery Grey POLY SHEEN has a much larger surface area to reflect the light, which is why it shines so beautifully This in turn is reflected in its huge color palette and brilliance It also has better elastic qualities and 50% higher tensile strength than rayon POLY SHEENPOLY SHEEN can be used in every situation and is particularly well suited for use with highly stressed textiles such as sports and leisurewear, children's clothes, leather, work clothing, jeans, terry cloth, catering and hospital laundry