The Athletic Works Deep Tissue Fitness Foam Roller features a hollow core design with patented three-dimensional textures on the outside to help loosen sore and tight muscles. The rigid inner core combined with the high-density outer shell can help increase circulation while the wide and narrow textures provide a deep massage and help eliminate muscle knots. The roller is ideal for use before and after any work-out and can be used anytime to help soothe tired muscles.