The Exo Terra Monsoon Remote Control works with the Exo Terra Monsoon RS400, enabling you to switch the unit to the On, Off and Cycle positions remotely. It’s also great for temporarily turning the unit On and Off; to increase the humidity manually; to test the nozzle performance; or to simply make sure the unit operates properly. Switching the unit On/Off from a distance will also help to prevent stress to the animals. 2 AAA batteries not included