These switches are for the electric vehicle function switch. There are 3 versions: 1). Red button switch (can be headlight switch, reverse switch, controller power switch etc.) 2). Green button switch (can be horn switch, cruise switch, e-brake switch etc.) 3). Double green button switch Red button: push the button once to turn on, and push again to turn off. Green button: push the button to turn on, and loose the button to turn off. The switch mounting hole diameter is 22mm.