Used by professionals and also amateursYellow (Extra light) perfect if you plan to do very complicated exercises that require minimal resistanceOrange (Light) perfect if you are a beginner or if you start exercising again after a long breakGreen (Medium) choose this band if you have some experience in trainingPurple (Heavy) you have to be strong enough to practice with this band, If you train regularly, choose this one.Black (Extra heavy) Perfect only for professionals who are advanced in strength training.It is so strong that you can also use it while doing pull-ups on a barDimensions:Width: 6.4 mm (extra light, yellow), 13 mm (light, orange), 22 mm (medium, green), 32 mm (hard, purple), 44 mm (extra hard, black)Weight: 1-9 Kg, 2-16 Kg, 5-23 Kg, 14-45 Kg,23-54 KgThickness: 4 mmCircumference: 208 cm