These ab straps are a worthwhile accessory to be used with the popular Iron Gym system, allowing you to challenge and strengthen your core abdominal muscles. Sturdy polyester construction can hold users up to 300 pounds, and the straps measure 11.5 by 13.1 inches (W x D). About Iron Gym As seen on TV, the Iron Gym (sold separately) offers challenging, muscle-building workouts at home or on the road -- anywhere there's a standard size door. The sturdy metal bar's unique design wraps around your doorframe, using leverage to remain securely in place without requiring the hassle or damage of inserting screws. When used properly, the Iron Gym helps strengthen and tone your entire upper body, and three different grip positions (narrow, wide, and neutral grips) let you switch up your body's positioning and continuously challenge your muscles.