GE Cync (formerly C by GE) Wire-Free Smart Dimmer + Color Control Switch. This battery-powered switch requires no wiring and can be mounted anywhere using the included adhesive tape or screws to control Cync smart bulbs, plugs, and other switches.
Battery: Uses one CR2032 coin cell battery, which typically lasts about two years.
Functionality: Beyond simple on/off, you can use the buttons to dim/brighten lights and tune white color temperatures (from warm to cool).
Mounting: It can be used as a handheld remote, stuck to a wall, or installed into an existing paddle-style wall plate