I only tend to see truck drivers with walkie-talkies these days as I drive past them. With the walkie-talkie smartphone handset, you can join in on that scene too.
The handset plugs in to the headphone port on any smartphone and has a microphone built in to the handset. To talk, you push the button. It has adjustable volume and the ability to pickup and end calls.
The handset requires 2 AAA batteries to run but other than that, its just plug and play.
Available from Perpetual Kid with a price tag of $19.99.