The Wireless Wall Switch transmitter is operated by a long life lithium battery and carries a signal up to 500 feet away in an open area. You can also add up to eight Skylink wireless transmitters, such as the Wireless Wall Switch (TB-318), Motion Sensor (ID-318) or Remote Controls (TC-318 Series), to control your Wall Switch receiver.

https://www.amazon.com/SK-8-Wireless-Anywhere-Lighting-Control/dp/B0052ROEB2