There's a lot of Adapter Choices. Sometimes more Information is Needed to Make the Correct Choice. Even After You Know What You Need, There is More Information Needed; Thread Details, Pressure Ratings, Installation Instructions, Torque Specification, etc… Get That Kind of Information Here.
DIN-2353 Metric Compression Technical Information
Thread Identification – North American Connections
Thread Identification – International Connections
General Adapter Information ie. Pressure Rating, Installation & Torque Specifications