Designed for light and speedy mobility, the strap can be rolled up to stash in a gym bag, suitcase, or overnight trip making it perfect for travel, gym, or in-home use. High-quality rubber material offers progressive resistance. Helps you isolate target muscles more effectively. Available 5 levels of resistance: Very Light (Yellow), Light (Green), Medium (Red), Heavy (Blue), and Ultra Heavy (Purple). Door strap sold separately.