Water-saving Tap / tap

Every time before we wash our hands, we will turn on the tap ahead,which will waste water. So why don't we figure out a way to wash hands and turn on the tap at the same time? The intelligent water-saving tap make it happen. When you start to wash hands,use your thumb to press the tap and the water comes out. Once you finish washing, you can just lift your hands and the tap will be turned off immediately.