The push button comes as a loose piece in the kit. It can be located on either end of the hose. I put mine next to the faucet to reduce the wand weight for traveling purposes.
The push button is designed to adjust water flow from full ON to a trickle. It will not completely shut the water flow OFF. That is a very convenient feature because it maintains water temperature when you increase the flow. As you have probably experienced, if the water flow is turn completely OFF, it will be either too hot or too cold for a few moments when you turn it back ON.
LeRoy
