Whisperlite is far upper left and not as good as other two , which were pre XGK MSR stoves., Middle stove is a 1973 Model 9 with a " Crimped Burner Bell, short legs for pots, and short flint striker stem. Not Model G ( which stood for Gas ) which was smooth bell, improved longer legs, and a longer flint striker stem. Pumps are the weak link in MSR stoves, and be sure to lub them up before a trip and bring extra o-rings,parts kit.. For their weight,, they are still the best in the business out melting a large amount of snow in a light packagable package..