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 nozzle performance, or to simply make sure the unit is functioning properly. Switching the unit on and off from a distance also helps prevent stress to your animals. Requires 2 AAA batteries (not included).