The Sunnydaze 2 Tier Solar-on-Demand Fountain has a durable resin casting and features a classic, two-tiered design. This birdbath is perfect for any garden or landscaped area with no need for an outlet! It can run on solar and battery back-up power. In prime sunlight conditions, the pump will be powered by solar energy while the solar panel will also recharge the batteries. To run on battery mode simply press the Battery On/Off button. On the battery mode it can run for up to 4 hrs on cloudy days or at night. When the battery power is depleted, the system will automatically change back to solar powered mode and start again when there is sufficient sunlight. A fully charged battery will operate up to 4 hours after the sun goes down. Operate it daily using the battery technology for consistent performance even in cloudy conditions, or leave the fountain off, charging the batteries for use when one would like.