Extra Ice Insert For Large Size Pro-Ice Low Back Wrap Model PI720. These replacement ice inserts are to either replace or provide additional inserts for the Large Size Pro-Ice lower back wrap, model PI720 (not included). Have spare inserts available in the freezer, while others are in use! These inserts are designed with individual, fast-freezing cells that easily shape to the lower back. Specifically configured to work in conjunction with the Pro-Ice Lower Back Ice Pack. The inserts are filled with a non-toxic, non-hazardous, food grade material with the same characteristics of water. Inserts will freeze at 27 degrees and with stay frozen longer then ice. Made in the USA. Note: When not in use inserts may be stored in the freezer (flat) or outside of the freezer (flat) in a cool & dry location.