The single largest contributing factor to fuel economy on your vehicle is the ?loose nut behind the wheel?. Driver input affects the amount of fuel you use more than anything else. The Ecometer by AutoMeter is a simple, plug and play device that connects to your vehicle?s OBDII port and allows for instantaneous monitoring of the exact fuel economy of your vehicle. So much more than a simple vacuum gauge, the Ecometer monitors a huge range of engine parameters to precisely determine how much you?re spending at the pump. A digital tach and speedometer are also included in it?s functions, as well as instant and cumulative fuel economy. Designed to work with nearly any 1996 and newer OBDII gasoline engine vehicle, the Ecometer can help you to easily realize fuel savings of up to 30% with only minor changes in driving habit.