Rear Hard Brake Line Size

I'm going to replace a rear wheel cylinder in my 65 Dart tonight, and I want to replace the LH hard line between the splitter on the axle and the wheel cylinder, because some yahoo in the past thought that Vice-Grips were the best tool for the job, and they hosed up the fitting.

Does anyone know what size and type of line I need to pick up on my way home?
I plan on cutting, bending and flaring it as needed. I just want to get the right size line/fittings.

Thanks!