Coats Ultra Polyester Bobbins #M Size 138 White (144 pack) deliver consistent, high-strength performance with prewound continuous filament polyester thread designed for commercial sewing machines. These M style bobbins in white use bonded polyester thread that stands up to demanding heavy duty sewing tasks, including upholstery, marine fabric, furniture upholstery, seat trims, and outdoor products. Their excellent resistance to abrasion and UV exposure ensures durable, noticeable stitches ideal for automotive and outdoor applications. Each pack contains 144 bobbins sized 138 / Tex 135, making them suitable for reliable, durable sewing on tough fabrics where lasting strength is essential.