trivia buzzer phone app

I’m planning to host a trivia/puzzle party soon, and I was thinking of getting a set of trivia buzzers, the kind where whoever buzzes in first locks out everyone else, etc.

But it occurred to me that there must be an iPhone or android app that does the same thing, and in this day and age, enough people have iPhones that we’d be able to get one per team.
Has anyone had any experience with such an app? Recommendations? There seem to be several on the iTunes store, but most of the have zero reviews, so it’s hard to tell whether any of them are any good.

(Ideally I’d like something that lets 6 or so competitors have their fingers on the buzzer, and then I ask a question, and I get informed of who buzzed in, and in what order…)