Furinno Rfitness Professional Loop Stretch Exercise Band 4-PC Set, RF1503-4 Professional strength - highly durable with superior tearing/snapping resistance Versatile, adaptable to multiple fitness levels from beginner to advance level Please follow proper instructions when exercising to avoid injury Light weight and perfect for travel RESISTANCE in lb-force at 100% to 300% elongation: Yellow - 7.5 to 13 lbs; green - 11.5 to 20.9 lbs; blue - 15 to 27.6 lbs; Red - 19.4 to 33.7 lbs