Features: nn--Durable Material: resistance bands are made of 100% silicone materialSilicone will not oxidize and turn white during use , which makes resistance bands soft and odorless and strong wear resistance and can withstand extreme tensile force. So that you can train without any worries of tear or wear. The exercise bands can remain high elastic after years of training and exercisingn--Multiple Resistance Levels: Customize your workouts with our pull up resistance band featuring 5 resistance levels, and each color is different resistance and width for different purposes.