The hard line is 3/16 line with a 10mm fitting on it. It is a standard 45 degree double flare. You can buy a line with the correct fitting at most auto parts stores. In fact, the small piece of hard line that I used to provide with my front stainless kits was purchased from an auto parts store. It cost me just as much to buy the individual pieces plus I had to do the flare. I would buy them double length, then cut them in half to install and AN3 fitting on the other end. I now just use a custom made braided line for that as well. You are probably not going to find a pre-fab hard line long enough line to go all the way from the back to the front at an auto parts store though. You could get a coupler, reflare what is left of the line and use a small pre-fab line from the coupler to the master cylinder. Another option is to buy hard line in bulk and flare both ends. A third option is to replace the entire hard line with stainless braided line. If doing that, I would go all the way from the master cylinder to the rear brake caliper. That way there are less fittings to leak. I only have the rear line from the hard line to the caliper in stock. I am about to place another brake line order though and could get you a custom line made.