Some models come with a built in water stop system. This feature makes a lot of sense if you will be changing the attachment often. This is because you will not have to go back to the tap/water faucet to turn off the water supply. You also will not have to wait until the water drains out from the hose before changing the attachment. There are some models in which all you have to do is pull out the attachment and attach the one you want to use.