Fig 207 API High Quality / Male Thread Union /Hammer Union for oil field Hammer union A hammer unions are widely used in the fluid or mud manifolds, Cementing and choke-and kill lines; it was divided by union color code, to use for lower-pressure, middle-pressure and high-pressure standard trim or H2S trim. We also manufacture compatible Hammer Union Seals (Lip Seal), O-ring, Lip seal rings, stainless steel backed seal rings, and brass backed seal rings for Weco Wing Union.