Fonzie’s blue windbreaker.

Townspeople of a certain age knows that Fonzie was coolest in his early appearances on Happy Days, when he wore the light blue windbreaker, not the leather jacket. What’s the Fonzie’s Light Blue Windbreaker of Rock, that is, the early, underrated, almost-forgotten stylistic mark (musical or otherwise) that is actually much cooler than what an artist would be known for?