4 pieces. Ultrasonic Solar Pest Repeller: The solar probe deflector vibrates and sends low frequency 400Hz sonic pulses every 30 seconds in all directions that do not physically harm these pests. You just feel uncomfortable and drive them away. Human mode to eliminate parasites: no death, no poison, no trap. The solar repellent is an eco-friendly way to minimize farm, yard, lawn or garden damage caused by moles, voles, goppers, mice and other rodents. 【Wide Coverage】Solar sound deadener emits in all directions up to 650 square meters. It is recommended to use multiple devices to achieve overlap. Usually it takes 2 weeks or more for the pests to leave the area. 【Efficient Solar Charging】A high-tech solar panel is built into the solar module repeller. No need for additional batteries, it is automatically recharged by the solar panel. It absorbs energy during the day and works throughout the night to prevent the return of mulleins and rodents. Technical specifications: Solar panel: 4.5V