1.The lowest flow resistance (actually 0) 2.Not stuck at work due to 3.In the greater pressure can be completely sealed NO.Parts NameCarbonSteel SeriesStainless steel SeriesLow Temperature SeriesAnti-Sulphur GB Standard NACE Standard1BallA105+HCr/ENPA351,CF8,CF8M,CF3,CF3MA352 LCB,LCC+ENPA105+HCr/ENPA351 CF8M+ENP2Bush Bearing PTFE,Metal +PTFE,Braided Graphite Fibre3Sealing RingPTFE,RPTFE,NYLON, ...