Designed for use with the Philips Hue smart bulbs (sold separately) Smart dimmer locks the existing toggle switch and keeps the switch always in on/up mode Rotary knob lets you switch on/off the bulb by tapping and adjust the brightness by rotating, giving you control over the bulb even when Wi-Fi is not available Easy 2-step set up lets you install the smart switch in 2 minutes by mounting the bracket over an existing toggle switch and snapping the knob on, no wiring required Programmable on the Hue app using the Hue V2 Smart Bridge