The Chambers Fireless Gas Range was a gas cook stove created by John E. Chambers in 1910, Two years after inventing his fireless cooker, John Chambers organized the Chambers Company in 1912. Chambers' patented method of manufacture used thick rock wool insulation to insulate the oven on all sides. This made it possible for the heat inside the oven to build up over a short period of time. The gas was then turned off, causing a series of internal dampers to close, which effectively isolated the oven compartment from the outside air. The food would continue to cook on retained heat, thus conserving fuel and reducing food shrinkage. This method of cooking, Chambers literature often claimed, also increased the food value of the cooked items.