Strongest and heaviest Hand sewing thread, cotton covered polyester Color: Navy Content: Cotton Wrapped Polyester Care: Wash in warm water. Oxygen bleach recommended, no chlorine bleach. Tumble dry, medium. Iron, high heat. Professional dry-cleaning in: perchloroethylene, hydrocarbons (heavy benzines); normal process. Size: 10 wt Weight/Yardage: 50 yds. Brand: Dual Duty Plus® Manufacturer: Coats