The Mobi Products battery cradle allows you to easily synchronize and charge your T-Mobile G1 with any USB-enabled computer. Just connect the cradle to your computer's USB and you are set. The phone is charged through your computer's USB port.
This cradle also features a spare battery charger - great to have if you have multiple batteries. If you want to use the cradle's spare battery charger, you also need to connect the bundled AC adapter. The AC adapter does not charge the phone, it only provides power to the battery slot.
NOTE: THIS CRADLE WILL ONLY WORK WITH OEM SIZED & OEM SIZED EXTENDED BATTERIES.