Nonflammability, weatherability, chemical resistance, low gas permeability, rather wide processability range, and low cost are six of the outstanding advantages of rigid PVC. Also, because 56.8% of its weight is chlorine, a nonpetroleum product, the effect of petroleum price increases is not as drastic as it has been on 100% petroleum-based polymers. Consequently, PVC also shows an advantage in cost stability. In summary, it is not pretentious to state that there is no other commodity polymer in the field with such a balance of processability, properties, cost, and cost stability. This explains the vital role it plays in the economy of the developing and underdeveloped countries, since it is the polymer that also offers the broadest spectrum of end uses.