These mobile gas chambers worked under the same principles as the stationary gas chambers: through a rubber hose the driver released pure CO from steel cylinders into the air tight special construction that was shaped like a box and placed on the carrier. The vans resembled moving vans or delivery lorries and they were labelled Kaiser’s Kaffee Geschäft (de) (“Kaiser's Coffee Shop”) for camouflage. They were not called "gas vans" at the time, but “Sonder-Wagen”, “Spezialwagen” (special vans) and “Entlausungswagen” (delousing vans).[7][6] The Lange commando killed patients in numerous hospitals in the Wartheland in 1940.