COATS & CLARK upholstery thread stands ready for demanding projects. This extra-strong, heavyweight thread is suitable for both machine and hand sewing of indoor and outdoor heavyweight fabrics. Constructed from a bonded 3-ply nylon, it stands up against weather, abrasion, mildew, and UV exposure. To get optimal results, it's best to use a size 18 machine needle and increase the stitch length. Ideal for upholstery, this thread brings durability and longevity to any project.