Iris Melrose Trilobal Polyester Thread, Pastels, Assorted Colors Trilobal Polyester Pastel Thread Assortment 24 pk Ideal for conventional and industrial machine stitching 100-percent polyester. 40 Weight. Ultra colorfast Trilobal Polyester Pastel Thread Assortment 24 pk Ideal for conventional and industrial machine stitching 100-percent polyester. 40 Weight. Ultra colorfast 100-percent polyester. 40 Weight. Ultra colorfast