Internal solid ABS hollow pipe with high density EVA pattern foam Pyramid shaped pressure points for added penetration Extra firm pressure 12" x 5" size, convenient for travel This Iron Body Fitness Acupoint foam roller features extra-firm pressure and pyramid-shaped points to help relieve tense muscles. Simply use your body weight and roll over tight areas to release contracted tissues so they regain their elasticity and increase circulation (myofacial release). As a self-massager it's great for stretching, flexibility, and injury prevention.