The Therapy Ball PLUS pair of self-massage balls measure about 2 3/4" in diameter and were developed by popular demand. They cover more surface area and add height to obtain a greater depth of pressure. Use them in their custom designed snug-grip mesh tote for spine rolls (top of the neck, down to the sacrum), as well as IT band & thigh rolls and so much more! The Therapy Ball PLUS self-massage balls are made from a special rubber that allows you to work out adhesions and tension, ultimately offering an exceptional deep tissue massage experience.