The Lutron ST-RD-BI is a Sunnata Companion Dimmer Switch used exclusively to extend multi-location control for the Sunnata PRO LED+ Touch Dimmer (ST-PRO-N-xx) in residential and light commercial installations. Not rated for standalone use, it mirrors the programming and lightbar status of the master dimmer, supporting up to five total control points when combined with up to four companion units. The decorator-style paddle and touch lightbar provide consistent on/off and dim/brighten operation, including a 30-second delayed fade-to-off. Biscuit finish.