The primary seal is formed by an interference fit between the disc hub and the seat flat. The secondary seal is an interference fit between the stem and seat stem hole. These seals prevent line media from coming into contact with other valve components. Ultraflo’s ultrathin one-piece Disc/Stem provides a high flow capacity with smooth flow characteristics that greatly reduce line media pressure drops. The disc edge is CNC machined and hand polished to produce bubble tight shut off, minimum torque and longer seat life. The Upper Stem Bushing absorbs operator side thrusts, provides precision alignment to ensure less wear and lowers operating torque. The Lower Stem Bushing eliminates gaulding and frozen stems. Both upper and lower bushings are heavy duty non-corrosive thermoplastic polymer. A Stem Packing prevents external contaminants from entering the stem bore. The Split Body design simplifies field maintenance by eliminating the need for special tools or presses during installation of replacement seats. All 300 Series valve bodies are designed to fit between ASME/ANSI 125 or 150 lb. flanges. Body Recesses accommodate lightweight flanges. Body Bolt materials are zinc plated carbon steel or stainless steel as standard.