gimmick

card 1 of 9 · context meaning

What does 'gimmick' mean in this sentence?

Epperlein and Tucker focus on two featherweight hopefuls: Dustin Poirier, a formidable contender who’s looking to parlay a history of schoolyard violence and street-fighting into a potential career, and Albert Stainback, a more thoughtful yet more erratic and undisciplined fighter whose chief gimmick is entering the ring wearing a hat like the one Malcolm McDowell wore in A Clockwork Orange.