It blocks robocalls. When someone calls you it checks the call against a database of robocallers and blocks known spam calls. It can also screen calls. It works pretty well, but it's not worth $7/week.

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roryirvine 6 days ago | parent [-]

Is that functionality not a standard part of ios? The stock Android dialler has had it since 2015...

	▲	imzadi 6 days ago \| parent [-]
		You can block unknown callers, but it just pushes them to voicemail. Robokiller intercepts the calls and keeps them off your phone completely.