I really love these trash cans. They use (Cx5) batteries, 3 for tall and 2 for small cans. Purchase them ahead of time so you can use the cans immediately. The small is roomy, larger than I imagined. The tall can has open and close buttons. Push open to keep lid open and close to close and reset back to auto close and open. I like that the sensor is not so sensitive that you get near it and it opens. This saves battery life. Excellent product!!!