This microphone-only headset can be used as part of a mobile installation to ensure not only consistent audio, but safe driving, too. It's lightweight, doesn't get in the way of your vision and gives good transmitted audio wherever your head is. See image for a suggest wiring circuit.
This, combined with some sort of safe/accessible PTT button, makes a great 2m/70cm mobile setup!
M0PZT says: "In my car, I use an Icom IC-2730 with a short length of cable from its RJ45 mic socket which breaks out to a phono socket for PTT (gearshift-mounted rocker-switch) and a 3.5mm socket for the Mic featuring integral 1k resistor and 0.22uF capacitor (1uF for full-range, 0.22 or 0.47uF to attenuate lower frequencies, ie: car/road noise) to power the electret capsule. A small extension speaker is velcroed to the door trim above my ear. This allows me to speak in a normal voice, even with the window open at 40mph with little-to-no road noise on my transmission."