1. Nbr: Restistan to Oil, Pressure and Wear, Good Elasticity and Mechanical Strength; Applicable to the Mediums Including Water, Oil, Alcohol, Etc from -20oc to 100oc 2. Epdm: Resistant to High or Low Temperatures, Ozone and Chemicals; Applicable to Weak Acids with Temperatures from -35oc to 150oc viton Resistant to Heat, Oil, Medicine and Chemical Reagents, Acid and Alkali with Medium Corrosive Degrees; Applicable to the Corrosive Mediums from -20oc to 180oc 3. Silica Gel: Resistant to Ozone, Aging, Acetic Acid, Ammonia and Alcohol; Applicable to Alcohol, Alkali, Etc from -50oc to 210oc 4. Chlorinated Rubber: Resistant to Freon, Petroleum; Applicable to Inorganic Acid, Alkali, Running from -30oc to 130oc