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.