The DSW-301 dual technology wall switch sensor turns lights OFF and ON based on occupancy. It combines the benefits of passive infrared (PIR) and ultrasonic detection technologies. The DSW-301 replaces existing wall switches and fits behind a standard decorator wall plate. Complies with 2011 NEC requirements. Zero-crossing for long relay life. Vandal resistant lens combines precise coverage with durability. Selectable walk-through mode turns lights off three minutes after initial occupancy if no motion is detected after the first 30 seconds. Test mode allows quick and easy adjustments. Selectable audible alert for impending shutoff. In automatic mode, sensor returns automatically to Auto-ON after lights are turned off manually; ideal for presentations. Four occupancy logic options to customize control to meet application needs. Optional light level sensing with simple setup. Service mode allows sensor to operate as a service switch in the unlikely event of a failure. Sensor coverage tested to NEMA Guide Publication WD 7-2000.