I just added a Rambler to my collection. As others have said in design, if not actual date of manufacture, seems a bit of a missing link between modern gas stoves with attached disposable gas cartridges and liquid fuel stoves. It proved easy to fill using a cheap butane canister and a lighter adaptor although, as ever, being outdoors is highly recommended. It produced muted flames until the jet was pricked then it basically became a portable Bunsen burner. Seems a design flaw to have aluminium pot supports, these must be prone to melting.