Waterproof Battery Tender - Maintain your 12-volt battery in peak condition. Extends battery life by 3-5 years. Specially designed to operate in wet, dry, hot, or cold conditions. Will not charge a dead battery. Great for maintaining batteries in cars and watercraft in storage. Input 100-240 vac, 50/60 Hz, Output 12 V dc @ 800 mA. 3-year warranty.