Trigger Point Foam Rollers are made of PVC and EVA material so it will not lose its shape after heavy use. These rollers are light weight, pressure-resistant, waterproof, sweat-proof, easy to clean, and durable. They help relieve sore muscles and tension. They also penetrate deep into the body for myofascial release, and they improve muscle flexibility. The triple grid massage zones of the roller mimics finger, palm and thumbs for effective massages before and after exercise. Ideal for use after workout to help reduce shoulders, arms, legs, back, buttocks, thighs, hamstrings, quads, calves lactic acid buildup after exercise. Suitable for home or outdoors.