Standard for use where expensive and corrosive liquids are being processed. Wedge construction of the secondary sealing element virtually eliminates leakage. A snap ring holds all parts together in a unitized construction design which eases installation and removal. Widely used in chemical processing, food processing, marine, nuclear service, offshore oil and refinery, petrochemical processing, rmaceutical, power generation, pulp and paper, wastewater, and water desalination industries.