Tender For tender for supply of u seal of 450nb bi-dir valve , slide gate 450nb bi-dir knife gate v/v , valve stem 450nb bi-dir knife gate v/v , body of 450nb bi-dir slry knife gate vlv , u seal of 350nb bi-dir valve , slide gate 350 nb bi-dir knife gate v/v , valve stem 350 nb bi-dir knife gate v/v , body of 350nb bi-dir slry knife gate vlv