How large is the copper line? 3/16''?

Does it fit into the fitting on the original gauge?

 

using nylon line for a little over a year on my car with no problem so far.

 

k cool i just snipped an inch off my nylon tube because i saw that it was kinked, it only broke when i was taking it off and now its reconnected. Good to know that this ---- doesn't often break and squirt oil in my interior.