Ground joint fittings are designed for high pressure air or water (ie. up to 500 psi) as well as steam (steam maximum 250 psi @ 450 deg F max) in plants, refineries, construction sites, or drilling applications (pressure ratings are for a guide ONLY as they vary based on service conditions, temperatures, etc.). Ground Joints are NOT for use with toxic fluids or flammable gases. The "Boss" brand features a unique, patented, nonmetallic polymer seal which is not subject to corrosion and offers resistance to chemicals and steam. Traditional ground joint fittings had a metal to metal seat, but the new polymer seat permits years of maintenance free service and will seal much easier in the field. The polymer seat will also minimize the loss of air or steam in your system, which provides more efficiency of equipment.
 

 Our "Boss" brand is manufactured domestically to strict tolerances for a consistent, reliable, and safe connection (for liability reasons, do not interchange Boss with unbranded products). We highly recommend the Boss Ground Joints due to the ease of use as well as the critical nature when using compressed air or steam, but we also offer an unbranded ground joint with a copper seal for less critical applications or for export. Interlocking bolt clamps MUST be checked and retightened before EACH use due to the cold flow/setting characteristics of rubber hose!