Worry-Free Feeding - You can leave knowing your fish are properly fed and cared for. Easy to install and program - Includes a simple getting started guide, step by step installation instructions and can be simply configured to be powered once or twice a day. Interchangeable Feeding Chambers - Includes 2 sizes of feeding chambers, a small (50g) for those with a relatively small aquarium and ensuring food is always fresh, and a larger (100g) ) for those who havea large ones in stock or if you plan to expand your aquarium in the future, there is no need to purchase another feeder. Adjustable volume control - delivers the right amount of food and ensures your fish are fed properly Battery Life - Powered by two AA batteries (included) for months of use. Package includes velcro, clip, battery, small and large power jars