Permatex Sensor Safe Blue RTV Silicone Gasket  is the original Permatex blue and makes reliable "formed-in-place" gaskets that resist shrinking, cracking and migrating.  Product cures to a strong, flexible rubber that seals flanges against leakage and resists oil and other shop fluids.  Coat pre-cut gaskets to increase reliabilty.  Temperature range -65 degrees Fahrenheit to 500 degrees Fahrenheit intermittent.  Low volatility.  Fills gaps to .25" when fully cured.