This Amazon Prime Day has a certain Ring to it.

The Ring Video Doorbell, which was once a “Shark Tank” reject, has already emerged as one of the hottest buys during Amazon’s AMZN, +0.50% annual summer sale, which has been extended to two days from July 15 through 16.

Amazon tends to save the best deals for its own smart devices for its July blowout, and the Ring is no exception.