This is a commonly misunderstood item.
THIS IS NOT A STANDALONE DIMMER OR SWITCH, IT'S A COMPANION OR ACCESSORY SWITCH AND REQUIRES ANOTHER DEVICE TO WORK. FOR WIRED 3-WAY, 4-WAY AND MULTI-LOCATION CIRCUITS WHEN USED WITH COMAPTIBLE MAESTRO DIMMER, SWITCH, OR SENSOR.
The Maestro Companion Switch is to be used in conjunction with compatible Maestro Dimmers, Switches, Timers. If you are not sure please ask.