ProSource Single Stackable Resistance Bands with Door Anchor and Exercise Guide, 5-50 lb, Heavy Duty Fitness Tube for Full-Body Exercises, P90X, Insanity, and Home Workouts COLOR-CODED RESISTANCE - 7 color-coded bands are sold individually but can be combined using durable metal carabiners to provide up to 23 levels of resistance DURABLE CONSTRUCTION - Made with a double-dipping process ensures these heavy duty, high performance latex tube bands prevent breaking and overstretching with normal use VERSATILE & EASY TO USE  Just one band can strengthen and tone all of your muscles through a full range of motion. Ideal for home workouts, Pilates exercises, P90X, rehabilitation, outdoor workouts, and travel  use them anywhere! FEATURES - Includes 2 soft foam handles for superior comfort, door anchor, and exercise guide. Great for shoulder raises, chest presses, back rows and more WEIGHT & SIZE: Measures 48-inches long and offers approximately 16-20 pounds of resistance. Simple clip-on system makes it easy to stack weight to keep workouts challenging and work various muscle groups