Yes4all Resistance Bands are made from 100% natural latex for lifetime use. SOLD AS SINGLE BAND & COMBO 4 BANDS. HOW TO CHOOSE YOUR BANDS? Choose a band based on your fitness level and the current number of repetitions you can complete. The thicker the band, the more assistance it gives for pull-ups, chins-ups, bar muscle ups and ring dips. Start with the thicker band then the thinner band or in case you need more assistance, you can switch from double bands to the thicker band and then the thinner band alone. Think about your purposes. If used for power lifting, the lighter bands are great for triceps and biceps exercises. The thicker bands are ideal for squats, deadlifts and lower body exercises. You can purchase multiple bands to vary the levels of tension. Purchase more than one band so you can have them handy as you move to the next level. Enjoy 3 resistance levels: one with the thicker band, one with the thinner band and one with two bands combined. Four resistance levels range from 10 LB to 150 LBS for your needs. 5/6” Resistance 10-60LB (Light – Lime Green band) 1.38” Resistance 30-90LB (Medium – Green band) 1.65′ Resistance 50-120LB (Heavy – Blue band) 2.5′ Resistance 60-150LB (Extra heavy – Red band) MULTI-FUNCTIONAL YES4ALL POWER BANDS It can be used for pull-ups, stretching, Pilates, squat flex, lateral walks, large muscle group and strength training. Try this and if you dont like it you can return it in 30 days. We pride ourselves on superior customer support. If you have any problems, we’re here to help.