Black Mountain Products strength resistance bands are the ideal fitness tool for Crossfit, weight training, assisted pull ups and much more. Each band measures 41" in length ranging from 1/2", 3/4" and 1" thick. Bands are perfect for gym, home, traveling and office use. Each loop resistance band is made from natural rubber to achieve ultimate resistance and durability. Each Black Mountain Products Crossfit band comes with a lifetime warranty. Band Strengths and Thickness: 1/2" - Blue 10-35lbs of Resistance 3/4" - Black 35-50lbs of Resistance 1" - Red 40-80lbs of Resistance.