The Bird-X deer guard electronic pest repeller uses ultrasonic sound waves to help effectively and humanely deter deer and other destructive animals from your property. Covers a full 4,000-sq. ft. of the area. Use in gardens to protect flowers and plants without mixing and spraying chemicals. The repeller features keyhole slots for easy mounting and you can choose to power it with batteries or an AC adapter (batteries sold separately). It may be operated with 4 C batteries (not included).