This is a quality LED headlight that plugs into the 6v controller light output of all Bafang and TSDZ2 mid-drive motors sold by Electrify Bike Co. (TSDZ2 requires an extra wire harness found here). The lights can be turned on and off via the display controls. When you put the display into night mode (hold down the plus button on most displays) the lights come on. The 860C has a light sensor and turns on automatically.