Our Thenx superior quality resistance bands are the perfect addition to enhance any work out. Whether you’re stretching, strength training, lifting weights, or doing yoga. These were designed for you to customize the intensity of your workout. They are lightweight and convenient for travel. Perfect for a beginner or advanced Thenx athlete. Challenge your muscles and intensify your work out today. Each band adds a different amount of resistance and assistance. Beginning with red for 10-35 lbs. (1/2 ” *4.5mm), black for 30-60 lbs. (3/4 ” *4.5mm), purple adds 40-80 lbs. (1.25 ” *4.5mm), and green adds 50-125 lbs (1.75 ” *4.5mm). Select your band depending on your training level.