There are two kinds of Google phone adapters, the car charger adapters and the wall charger adapters. The Google phone car charger adapters utilize the cigarette lighter of your automobile. The Google phone wall charger plugs right into any wall outlet in your home. Another type of Google phone adapter will allow your favorite stereo 3.5mm headphones to fit in the headset jack of your phone. Since the T-Mobile G1 has no 3.5mm headphone jack anyone who wishes higher quality sound than is available with the earbuds supplied with the unit will have to purchase an adapter.