It operates on 2 "D" batteries (not included) to provide up to 100 hours of running time, with two speeds for maximum efficiency and powerful air circulation. Designed to be ultra quiet, it will never frighten your pets. They remain cool, calm and comfortable, even on hot muggy days. The fan easily clips onto most standard cages, crates or pet carriers. At home or on the road it’s the best way to help your pets keep their cool. Ideal for shows and short or long trips.