The Triplett TMP230 Deep Fryer Oil Tester simultaneously displays Temperature and TPM (Total Polar Materials). It will acccurately measure cooking oil for correct temperature setting and provides the TPM value (%) which is an indicator for the aging of the cooking oil. The higher the % TPM reading, the more aged the oil is so you will know exactly when it has to be replaced. Includes (2) AAA batteries and carrying case.