Features corrugated ribs to prevent flashover. Designed to eliminate combustion gas leakage and for greater spark transfer, greater heat transfer, high dielectric strength, improved anti-fouling and corrosion resistance. Product Features:Triple gasket-sealing process virtually eliminates gas leakage past the shell99% highly pure alumina silicate insulator enables use of longer insulator noses to reduce fouling3-step trivalent-plating process uses silver chromate and zinc for maximum corrosion resistance