Wilson Predator Sonic-Repel Max is a portable, battery-operated device designed to repel rodents. It electronically produces ultrasonic sound waves that make mice and rats uncomfortable, which makes them leave any sound-protected area. Perfect for use in homes, offices, sheds or covered outbuildings, warehouses, restaurants, garages, schools, cottages, aparent buildings, farm buildings, private boats and RVs, domestic kennels, and stables. Will work for up to 4 months and covers 2,500 square feet. Batteries not included.