For use with 0-10V, 4 wire, 120V 10A/277V 5A fluorescent and LED dimming ballasts. Convenient operation combines ON/OFF paddle switch with separate slider for dimming control. Preset, single pole and 3-way operation. White LED glows when dimmer is OFF for easy location in the dark. Wider slide control for easier dimming operation. Constant memory returns lights to previous level after a power failure. No derating required for one- and two-gang applications.