Teflon Bellow Mechanical Seal series TB420 are designed for extreme corrosive chemical applications including concentrated Acids, Salts, Strong Oxidizing and reducing the agents & chemically active Organics Compounds. All components which come in contact with the Liquid to be sealed are made of chemically inert material. Metallic Components, Clamping Ring and springs are located outside the Media. TB420 Single coil springs with Halar Coating improve life as compared to multi spring.