ECO-WORTHY 5W Portable Solar Trickle Charger perfect trickle charger/maintainer for 12V batteries of cars, motorcycles, boats, snowmobiles, tractors etc. The dimensions is 8.7*7.5 inches. Charging 12V battery in emergency, suitable for the vehicles in outdoor work, travel or camping training, and the vehicles are put for a long time. Easy to install and completely maintenance-free. Environmental protection and energy saving, built-in blocking diode to prevent reverse discharge, not only maintains the battery lifetime but also extends its usage life, keep the battery from drain dead. Please remove the protective plastic film from the right corner of the panel before using it. The cigarette plug option only works if it has constant power when the key is out of the ignition. When you start the car, please remove the solar panel from the car battery. The suckers help to attach the solar panel on the smooth surface like windshield.