... corrosion 4.protect electrode 5.high voltage resistance High purity&heating-resistanceOD range 1.2mm-360mm, Silicon Dioxide>99.995 ... 1100 DEG C after 15 minutes, in 20 degrees C water quench, repeat the test 3 times, no crack, notch ... shape, etc.4. OEM allowed5. certificate :CE6. application fields:heating element, drying equipment, cooking device, medical equipment,fry&baking equipment, sterilizing ...