? Brand-new method of circuit design, by adopting Layout to design the capacitive reactance. ? The circuit is of simple structure, which make it easy to debug. ? Has been tested in multiple environment. The testing result shows its more stable performance than other similar products. ? Nickel-plated brass F-ports for maximum corrosion- resistance on drop interface. ? Can be upgraded directly only by replacing the front faceplate, needless to change the whole unit.