The WSD is a stylish, easy to install, and simple to use Wall Switch Decorator style Passive Infrared PIR sensor. It is ideal for private offices, copy rooms, closets, or any small enclosed space without obstructions. A user programmable time delay ensures that once the room is vacated the sensor will time out and turn off the lights.Additionally, the WSD sensor has several On Modes and Switch Modes that can be programmed using the front push-button. For rooms with obstructions, the Dual Technology WSD PDT Series sensor is recommended. Additionally, all WSD Family sensors have a patent-pending wiring method that enables them to function either with or without a neutral connection. WSD units come pre-configured for wiring without a neutral; however, if connection to neutral is required by code, contractorscan convert the unit in seconds.