The 12V On/Off Switch is used as a backup to control the heat of your heated gear. When turned on your heated clothing will be heated at full strength (+135°F). When turned off there will be no heat. The On/Off Switch is an alternative option in case something happens to your main temperature controller and you need heat in a pinch.12" lengthNot recommended as a permanent heat control solution due to the lack of temperature controlsMay cause burns with continuous, long-term useREQUIRED FOR OPERATION (Sold Separately): 12V Battery Harness OR 12V Accessory PlugWARNING: Failure to use product(s) as instructed or alter them in any way could result in damage to the products, cause them to malfunction, and/or cause bodily harm.