321 STRONG Exercise Resistance Bands - Individual or Complete Set for Assisted Pull Ups, Stretching, and Strength Training We are the only manufacturer to print the resistance of the bands right on the side , so you know you have the right resistance Use lighter workout bands to stretch . Use a heavier resistance band for an assisted pull up Place our resistance loops under your feet and use like dumbells Combine multiple exercise bands for custom levels of fitness . Purchase individually or as a set Each of these resistance bands are 41 inch loops , long enough for pull up assistance 100% natural latex rubber Resistance level printed right on the band 82 inches of rubber formed into a 41 inch loop Can be combined for custom resistance levels 4.5 mm thick, constructed of multiple layers of rubber Durable and built to last a lifetime Lightweight and easily portable Increase flexibility Restore mobility Enhanced warm up and cool down stretching Target specific muscle groups Build and tone muscle Develop higher jumping ability Recover from injuries Perform more reps with offset body weight