Retained Heat
was always a Chambers feature, beginning with John Chambers first models in the 1920s, until their lower "economy" line was introduced in the late '60s, and those were built by Thermador or Caloric or someone else. The real Chambers had the features listed above, and one could cook a 20 lb turkey with a hour of heat, then turning off the gas or electricity for the remaing 3 or 4 hours. One had to learn a new cooking/baking style when cooking in a Chambers oven.
Baltimore had a very active Chambers dealer, and they are frequently seen there. Our gas version came from the Hamilton neighborhood of Baltimore (our hometown).
A new $3000 Wolf cooktop feels lke a piece of junk compared to a vintage Chambers 42-4BH 42" In-A-Top stainless cooktop circa 1956. Available in electric or gas models and 27", 33" and 42" sizes. The smallest have no griddle. We have a 42" one waiting in the garage, hat we've never installed, and the smaller 27" version at the lake house.
Your customer has good taste, John, once one has used a Chambers, there is no substitute.