Air bubbles rise beside an empty copper helmet submerged in a glass test tank. The helmet's broad lower flange rests on a dark support, keeping its rounded body upright. A thick hose curves over the tank edge and connects at the side. Small bubbles leave the nearby valve and gather into a loose column on their way to the surface.

Brass windows interrupt the darker copper shell. The large front opening has a circular rim and visible fasteners, while smaller ports show protective bars. Scratches, tarnish and irregular warm highlights distinguish the old metal from the green-tinted water around it. The corner of the glass tank bends and doubles some background lines through refraction.

Beyond the tank, tall gridded windows and heavy workshop equipment establish a practical testing space. A hanging lamp adds a small warm reflection to the helmet, while cooler daylight reaches the wet bench and scattered metal tools. The scene makes an otherwise concealed air path visible through a simple stream of bubbles.