The F Series group of PVC heat stabilizers are suitable for food, medical and plastisol applications. F31 is ideal for industrial use whereas F40 is specifically formulated for medicinal/food contact and toys applications. All F Series stabilizers are clear liquids. These products should be kept protected in a dry place. The containers must always be kept tightly closed. For best results, we recommend 2 to 3 parts per hundred resins (phr), based on the processing conditions and desired end results.