The Pilot Better Retractable is a very smooth, especially for a ball point. It comes in red, blue and black with matching barrels for quick recognition.

There's a ribbed grip where most newer pens have rubber, but it's better than smooth plastic, and the rubber from a lot newer pens loosen and become problematic in hot weather.

The Better Retractable comes in "fine" and "medium" points, which means .5 mm and .7 mm. The only problem I usually have is finding it in red and blue.