1. what is over load protection If the user uses the unit over load, it might shorten the life of the unit or damage the unit. To prevent this, we design one overload protection to shut down the unit automatically if overload happen (normally, it is 120% of the rated power). If you want to start the unit, please remove the plug from power, then plug again to start to work. 2.when be short citcuit occurs? and after protection occurs, can it start to work automatically? If the end equipment short-circuits or there is a metal contact to the AC plug, the short circuits protection will raise. If you want to start the unit, please remove the plug from power, then plug again to start to work. 3.Does Universal Socket means to work in all countires with different sockets? Universal socket is designed according to the socket from different countries, it works with different plugs in different countries, such as US, Japan, ?????Europe, India, Korean, UK etc.The Europe socket design is better and more safety. If the customer requires only Europe socket, we need to make new tool. But please notice that the Europe socket is bigger than Universal socket in design and there is no place for such socket in some small or slim products.