Thermoplastic or Elastomeric seats are inserted in the metallic holder (seat ring) to deliver smooth seating action within a ball valve. The main characteristics of a delicate-seated ball valve are Ball valves operate by rotating the ball 90-levels to align or unalign the bore with inlet and outlet ports In https://manueljylwi.wikibriefing.com/3349142/helping_the_others_realize_the_advantages_of_ball_valves