The Battery Tender Solar Charger 021-1172 is a compact and portable solar panel that is designed to charge and maintain 12-volt lead-acid batteries. It is equipped with a built-in smart charging controller that ensures efficient and safe charging, while also preventing overcharging. This solar charger is ideal for use with cars, motorcycles, boats, and other vehicles that may sit idle for extended periods of time. It is weatherproof and can be easily mounted on a windshield or dashboard using the included suction cups. The Battery Tender Solar Charger 021-1172 is a reliable and convenient solution for keeping your batteries charged and ready to use.