... floats) downstream to maintain close contact with downstream seat to form a reliable seal under the medium pressure ... when closes. The seat special design has the wearing complementary structure to ensure ... 13CR,2CR13,F304.F316,STEM: 13CR,2CR13,F304.F316,SEAT: A105 +STL,.F316 ,F304,Sealing face:Hard ... soft seal :PTFE, PEEK, nylon, RPTFE unibody one piece floating ball valve