Those measurements were actually incorrect and were for the Livewire. The listing has been corrected. The screen measurements are 1-3/4" by 2-1/2". The device is 2-3/4" at its widest by 6-1/4" at its tallest with its wiring plug by 3/4" deep. The device does not need to say plugged in unless you're monitoring your vehicle. If you're just loading a tune, the device can be unplugged as soon as the upload process is complete.