There is no electronic inside. It is all soldering work. I never like the one  made by Neptune because the grounding is all shared on one connection. You can't  disconnect one without disconnecting others. You can't even connect all six  ground wires to one connection. It is simply stupid. Hence I made my own version  using DC power connections. If you are handy, you can google to learn how to do  it. However the parts you need is already $20. You decide if it is worth your  time and effort.