Double Spherical Rubber Joints Standard:ISO,ANSI,DIN,JIS SUITABLE MEDIUM: WATER Double Spherical Rubber JointsSubject: Polarity RubberInside Linning: Nylon BurlapSkeleton: Hard Steel WireFlange: Carbon Steel,ZincificationCertificate: ISO9001,ISO14001,CE,API 6D,GOST,KS