The following unsourced paragraph about a similarly named piece of equipment was previously put in the summary of this article:
In some countries hydrants in streets are below ground level. Fire trucks carry standpipes and key, and there are pry bars on the truck. The bar is used to lift a cover in the road, exposing the hydrant. The standpipe is then "sunk" into the hydrant, and the hose is connected to the exposed ends of the standpipe. The bar is then combined with the key, and is used to turn the hydrant on and off.