Everlast Mixed Martial Arts C3 Foam Heavy Bag (Red, 100-Pound) Durable polycanvas wrap filled with C3 Closed Cell Foam Technology provides increased cushioning and force dispersion while its resilient design maintains bag integrity. Specially blended filler mix of sanitized synthetic and natural fibers provide resilient shock absorbency. Heavy duty nylon straps provide security and safety, while the double end loop provides increased functionality. Featuring C3 Foam Technologies