The gauge adaptor has a flat mating surface to correspond to the male thread on a standard gauge. Seal is made with the use of a rubber or PTFE washer. You can then connect a gauge via this adaptor to any BSP port or hose using either the 60 deg cone or a bonded seal.
PTFE Washer can be ordered separately - see related products section.
Pressure Ratings Nut Tightening Torques