The item is a trolley-mounted fire extinguisher discharge hose with a gun and nozzle, designed for dry chemical powder systems.
The assembly typically include a black rubber or PVC hose, commonly available in length of 3 to 5 inches.
It features a metal discharge gun with a trigger valve at one end for controlling the extinguishing agent.
The opposite end is the threaded metal fitting meant for attachment to a wheeled trolley fire extinguisher unit.