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. The battery-operated Wi-Fi enabled smart home security system connects with Alexa-enabled devices like the Echo Show and Echo Dot so that users can see, hear and speak to anyone that comes to their door. It can also send alerts to residents via their phones, tablets and PCs any time motion is detected at the door, or when the doorbell is pressed. It’s on sale for its lowest price ever according to both Tech Radar and Amazon price tracker CamelCamelCamel at $69.99, or $30 off its usual $99.99 price tag.

An even better deal throws in an Amazon Echo Dot with the Ring Video Doorbell for the same price ($69.99), which would normally be $149.98 together. As a result, searches for the Ring Video Doorbell spiked on Google on Monday morning, and it was among Amazon’s best sellers in both its electronics and Amazon devices categories.

And the even more souped-up Ring Video Doorbell Pro, which comes with four faceplates, a better camera, and is hard-wired into an existing doorbell system so that the user doesn’t have to worry about changing batteries, is on sale for $169, or $80 less than its original price. And you can also get a free Echo Dot thrown in with another Prime Day bundle special.The Ring — or DoorBot, as it was originally known — was actually pitched by creator Jamie Siminoff on the Disney-owned ABC’s “Shark Tank” in 2013, when it was already making $1 million in sales. But Softkey founder Kevin O’Leary was the only one of the “sharks” (aka entrepreneurs/judges who offered to invest in the pitched products on the show) who was interested, but he wanted a bigger bite of the profits than Siminoff was comfortable with. But Amazon came knocking in 2018, and bought the company for $1 billion.

Global spending on video doorbells like the Ring series or the Google GOOG, +0.48% Nest Hello is expected to almost triple from $500 million last year to $1.4 billion through 2023, according to data insights firm Strategy Analytics.

Consumer Reports included the Ring Video Doorbell on its list of Best Video Doorbells of 2019 published earlier this month (along with the Nest Hello), and praised it for being an affordable security option to see who’s at the door and to catch porch pirates stealing packages, although it noted that video quality could be better. It listed the upgraded version, the Ring Video Doorbell 2, as an slightly more expensive option with much better video quality. It’s currently marked down to $139 (from $199) for Prime Day.

But like the many other smart home assistants that record and store video and audio, the Ring has been raised privacy concerns. CNET recently reported that Amazon is helping police officers build a surveillance network using the footage from Ring doorbells, noting that more than 50 local police departments across the country have joined with Ring over the last two years.

Deciding whether to spring for a Ring, or any other Prime Day deals? Check out these MarketWatch Prime Day shopping guides, including:

10 kick-ass Amazon Prime Day deals not to miss, according to deal pros

What NOT to buy on Amazon Prime Day

And for those boycotting Amazon and Prime Day today, or if you’re just looking for the best deal among the online giant’s competitors, here’s how Amazon’s deals stack up against sales happening at Walmart WMT, +0.33% Target TGT, -0.83% eBay EBAY, +0.52% Kohl’s KSS, +1.13% Macy’s M, +0.59% and Best Buy BBY, +0.98% this week.