The Outbak Gutbuster slings were developed to trim, tone and tighten your abdominal muscles achieving maximum muscularity in your midsection.To use, attach to any secure chin-up bar or similar apparatus. Put your arms through the loops and support your own body weight from under the arm-pits. Hold the Gutbuster with your hands above shoulder height, then push your hips slightly forward.The Outbak Gutbuster is designed for leg raises, knee raises, oblique bends and back stretching.