So I am at my local hose repair business and I let him know that my 1/4 inch hoses are from a Kubota...that's when everything got slowed down...So he measured the threads at 18 threads per inch but my question is...are these threads NPT or Metric? He claimed that they were essentially impossible to tell the difference...I'm not so sure about that, so how do I tell the NPT from the Metric? Thank you.