Conveniently control four X10 receiver modules with an X10 wall switch by installing the X10 PRO 4-Button Keypad Plus Transmitter Base Kit. The in-wall keypad enables manual control for four X10 receivers on the powerline. Hit one side of a rocker switch to turn its corresponding receiver on, and hit the other side to turn it off! The "behind-the-scenes" transmitter base mounts in a single-gang wall box and connects to Hot and Neutral wires. The included keypad attaches to the face of the transmitter, providing a clean, elegant appearance. How It Works: The transmitter base can control multiple X10 receivers by running the Unit Number Addresses in sequential order. In other words, if you have the dials on the transmitter base set to House Code B and Unit Code 4, the keypad's four buttons will control the X10 receivers set to House Code B and Unit Codes 4, 5, 6 and 7. The top button will control Unit Code 4, the next button below will control Unit Code 5, and so on. CONTENTS: Wall Transmitter Base Module, 4-Button Keypad. NOTES: 1. Wallplate not included. 2. Due to X10 Product changes, these Transmitter Bases are not compatible with Transmitter Bases sold before July 2007.