Classic faucet design - Looks like a car gear

Water conservation is still one of the easiest ways to save energy (it's energy!). And preserve our planet. If you do not tell you the truth, I am afraid you would hardly realize that this car gear like design is actually a faucet. The designer cleverly grafted this classic design on the car to the design of the faucet, with "neutral" corresponding to "off", with 1, 2, 3, 4 gear corresponding to the different intensity of the water flow, it looks really beautiful, but also water saving function. However, brand designer Shen Di did not mention how to control the temperature, hoping to further understand.