This QDC (Quick Disconnect Charger) plugs directly into the standard Battery Tender quick disconnect charge cable that is already installed on your bike. With LCD display that shows actual voltage. The three LEDs show 'Green' greater than 12.0V, 'Yellow' 12.0V to 11.6V (low)and 'Red' Less than 11.6V (discharged). Dimensions 13cm long x 3cm thick.