Also, I strongly recommend the following mono earphone for your radio. Since the Pro-106 tends to have a lower volume when compared with the GRE version, some people activate the "audio boost" on the radio. If you are using Win500, it is near the the area where you adjust the alarms & LED behavior.
If I'm not piping my radio into my stereo, like on trips with my wife, I use two of these earplugs, one for the scanner & one for the CB. Amazon.com: Accessories Unlimited AUEPD1 Earphone With 3.5Mm Plug: Cell Phones & Accessories
You used to be able to find these at most truck stops, but for some reason, they are hard to find.
I have a professional grade earphone like the ones LE uses with the clear spiral cord, fits inside the ear canal. While it delivers a solid sound, it is still diminished when compared with the aforementioned earphone. The earphone I recommended is positioned over the ear canal instead of inside. It uses a fairly large speaker as well.