Hy Jerry A, if it's compression here are the Weatherhead p/ns for the compression sleeve and the nut for the line, you didn't tell us what size tubing so here are a few numbers
compression sleeve nut
1/8" 60X2 61X2
3/16" 60X3 61X3
1/4" 60X4 61X4
I'm sure you get the idea, hope that helps.