This is a standard tube nut for 3/16" brake tubing. The outside has 3/8-24 SAE threads all the way to the end, and the inside is contoured to fit a standard SAE 45 degree inverted (double) flare on common 3/16" or 4.75mm steel brake tubing. The tip has no unthreaded lead portion, so the port must be threaded all the way down (not for use on British ports requiring a "bubble" or convex flare). Sold individually. Tubing not included.