This is a nitrogen Nipple and Nut. It is CGA580 style for a Nitrogen Regulator. You can order this with a left hand thread or a right hand thread. You need to know if you regulator is left or right hand thread. For example, Taprite and TOF regulators have a left hand thread on the high pressure side and Chudnow has a right hand thread. Also make absolutely sure your regulator is rated for the higher pressure of Nitrogen gas. DO NO use these with Taprite CO2 regulators with plastic bonnets. They are not rated for this high of pressure.
WARNING: This product can expose you to lead, which is known to the state of California to cause cancer, birth defects and other reproductive harm. For more information go to: www.P65Warnings.ca.gov.