Speed heat and Heat minder both debuted in 1955.
'All models will be available in White Porcelain finish. In addition, exterior colors of Stratford Yellow and Sherwood Green will be optional on seven models-the RV-25, RV-25G, RV-38, RV-38G, RV-60, RV-70, and RV-70G. Ranges with colored exteriors will be identified, as in the past, by number suffixes-"1" to identify yellow and "2" to identify green.'
The Speed heat and Heat minder were ONLY available on four 40" models that year.