ACDelco Professional, premium aftermarket Black Heater Hoses are constructed with EPDM rubber for extra-long service life and good resistance to high temperatures for extended periods of time. They are composed of specially blended materials to help resist electrochemical degradation (ECD), the leading cause of hose failure. ACDelco Professional Black Heater Hoses are temperature rated from -40 degrees Fahrenheit to +257 degrees Fahrenheit (-40 degrees Celsius to +125 degrees Celsius) and are unaffected by high cooling system pressures, most coolants, and non-oil based coolant additives. Do not use for fuel or oil transfer applications. These premium aftermarket replacement black heater hoses are manufactured to meet your expectations for fit, form, and function.