1.Black wire is direct to earth on the outboard,Emergency kill, stop switch with lanyard for all outboard motors 2.Many of the older outboards do not offer protection if you should fall out of your boat by cutting, stopping the engines ignition 3.This essential device has a lanyard that wraps around your wrist or clips onto your clothing, it stop the engine in the event of you having an accident on the water 4.The switch is open circuit and closed when the activated by pulling on the lanyard,You may also activate by simply pressing on the red button 5.If you have no spark to your outboards ignition system it may well be that your existing cut of switch may faulty or be stuck in the off position and need to be replaced Material:ABS colour:Black + red Package Contents: 20 x Emergency Kill Stop Switch 20 x Kill Switch Safety Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.