Melting Sealing hammer unions are available in a wide range of sizes and in working pressures to 15,000 psi. Pressure seal, non-pressure seal, and welded styles are offered in various sizes. All Melting Sealing hammer unions provide pressure-tight, positive sealing and are available for standard services and sour gas models. Melting Sealing hammer unions for sour gas services are specially heat-treated for controlled hardness and utilises fluorocarbon elastomer seal rings.