ball check valve,double union check valve 1.Size:1/2",3/4",1",1-1/4",1-1/2",2" 2.Standard:ANSI,JIS,DIN,BS OR ... BSPT,NPT ball check valve,double union check valve 1.Description1).Name: pvc union2).size: 1/2", 3 ... /2", 2", 3", 4".3).color: grey, white4).standard: ANSI,JIS,DIN,BS OR NPT,BSPT5).Working condition:1.0Mpa6).end connector: socket7 ...