Purchased on Amazon as a spare, operation confirmed, includes batteries, for repelling pests like mice. I feel like it had some effect. Product Details Top Highlights Brand: ISOTRONIC Color: Gray Style: Compact and practical Material: Plastic Item Weight: 156 grams Electric: Yes Repels mice with ultrasonic waves that mice dislike. By placing it in areas where mice habitually appear, they will feel uncomfortable and change their dwelling. The ultrasonic range is up to 40㎡. Mice will feel uncomfortable and start looking for a different dwelling. Emission time: 5 seconds on, 25 seconds off. It operates normally even during the off period. Uses 4 AA batteries (included). No power cable needed, making it portable and easy to use. Just two steps: insert the batteries and turn it on. Since it doesn't use harmful chemicals, it's safe for people and pets without harming the mice.