Whether your goal is building lean muscle mass or shedding excess body fat, ZoN Resistance Tubes will help you reach your goals. Use the tubes to burn fat through high-rep, low-resistance exercises, or to gain lean muscle mass through low-rep, high-resistance exercises. Isolate individual muscles or use as a full range of motion exerciser. Resistance tubes provide a safe, proven, do-anywhere routine to build strength and improve tone; no bulky metal weights needed. Now available in 4 resistance levels to suit your fitness capabilities.