What tool is utilized specifically to stop the flow of water in a hose line?

The hose clamp is designed to effectively stop the flow of water in a hose line. It works by physically constricting the hose, creating a seal that prevents water from continuing its passage through the hose. This capability is crucial in firefighting operations when it is necessary to temporarily halt the supply of water to inspect, repair, or change hose lines without shutting down the entire water supply. This tool ensures safety and efficiency during fire suppression activities by allowing firefighters to manage water flow as needed.

In contrast, the other tools listed serve different functions. The ball valve is used to control flow by opening or closing a pathway but does not specifically clamp down on the hose. A Siamese connection is for merging multiple hose lines into one, facilitating water supply but not stopping flow. A flow meter measures the amount of water flowing through a line but does not control or stop the flow. Thus, the hose clamp is the most suitable tool for the specific purpose of halting water flow in a hose line.