While the derailleur bike was sweeping America in the early 1960s, the idea arose that the same phenomenon could occur elsewhere - though this would require a cheaper derailleur as not everyone (in fact no one) was as rich as the Americans.
Simplex had already developed its plastic Simplex Prestige deraileur with half an eye on this opportunity. Huret's response was the design shown in this patent - the Huret Svelto - a proper metal derailleur, but reduced to its only its most essential features.
As late as 1976 I was happily selling basic five and ten speed bikes sporting Huret Sveltos.
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