14″ Ply-U-Flex Massage Stick sold with the Muscle Healing Oil. The massage stick must be used with a lubricant; otherwise, it hurts the skin. The Ply-U-Flex Massage Stick with the Muscle Healing Oil allows you to use enough pressure to open up the muscle tissue to remove toxins. Made from a combination of fifteen different Chinese herbs, this oil makes a big difference in muscle health. It penetrates the skin and gives the muscles the nutrition they need to feel good.