MELROSE-Machine Embroidery Thread: 600 yard spool. Superior coverage and excellent tensile strength result in smooth and consistent embroidery runs. Melrose Polyester offers vibrant non-fade colors even when washed in bleach and warm water. 600 yard double snap spool; More value per yard as compared to traditional 250-275 yard spools. Ideal for conventional and industrial machine stitching. 100-percent polyester. 40 Weight. Ultra colorfast.