This method is intended to define the continuous upper temperature resistance (CUTR) of thermoplastic elastomers and thermoset rubber with durometer hardness <=90 Shore A, to oxidation or other degradation when exposed solely to hot air for an extended period of time This method established the upper thermal aging limits of commercially available compounds as measured at 23 °C by retention of at least 50% original elongation and tensile at break after 1008 h of heat aging. This method does not take into account nor measure the effects of stress, environment, or temperature variations on the thermal aging characteristics of the materials tested.