Completely waterproof case, has a 3-point mounting back which allows it to be securely attached to any location. Once mounted the clock case twists on creating a tight water-resistant seal as well as permanent mounting. A silent sweep seconds hand (no ticking) gracefully sweeps around the dial with bold easy-to-read numbers. The sky-blue case has a passing white cumulus cloud effect to give it a casual look. The gasketed glass protective lens keeps moisture out of the dial. This clock is a great choice for Recreational vehicles, boats and anywhere a high-humidity or water-resistant timepiece can be used. Uses (1) AA battery, not included.