The function of the water stop screw: the function of the water stop screw is to ensure that the width of the wall is not affected when it is disturbed. It is break-through inside and outside the wall, so water stop sheet should be added, the function of the water stop sheet is to block the penetration of leakage water from the inside or outside. It is called the water stop screw if the water stop piece is added to the middle of the wall positioning screw to stop water.