Product Features: Ball is diamond turned, after molding, to make it spherically perfect, which provides precise contact between ball and seats. FKM (viton type) seals. Precision molded in polypropylene. Polypropylene is reinforced with fiberglass for additional strength. PTFE self-lubricating stem bushings and seats cannot stick or bind. Self-aligning ball moves freely against the PTFE seats for smooth operation. The valve opens and closes with very little pressure on the handle.