Barrel Jack Power Switch - Black (Green Stuff World)Barrel Jack Power Switch A barrel jack power switch is a type of switch that is commonly used to power modeling equipment such as LED lights, hobby lamps, and other devices. It is called a barrel jack because it consists of a cylindrical barrel that plugs into a corresponding jack, and it is typically used to connect an external power supply to any device. This switch is useful because it allows the user to quickly and easily turn the device on and