To install the August Doorbell Cam Pro, you need a mechanical doorbell chime since it doesn't work with digital chimes. Unlike SkyBell and Ring, it doesn't have an adapter or add on for digital chime functionality. As with most video doorbells, this one has a built in battery, but it can't run off the battery for very long, less than a day in our experience. August covers this product with a one year warranty. Read the full reviewMost Advanced FeaturesNest HelloReasons to BuyPre recorded responses and advanced detection featuresReasons to AvoidMost expensive video storage subscriptionRead the full Nest Hello review$173. 88 View at eBayRecommended Retailer$189View at Google Store$229View at Walmart?Nest Hello comes with the most advanced features we've seen in a smart doorbell: facial recognition, people detection and pre recorded responses you can use to relay information to visitors without answering a call. Our favorite feature was the pre recorded responses that inform visitors to leave a package, wait for someone to come to the door or saying no one is available. During our tests, we found that the Nest Hello produced the second best video quality, tying with RemoBell, only Ring Pro had better video. Nest Hello has a slim form factor that fits on most doorframes and is the only video doorbell we reviewed with a two year warranty. It's a great option if you have other Nest devices in your smart home but has limited smart home functionality otherwise. If you want to record video, you can pay $5 a month, which is more expensive than other video doorbell storage plans in our comparison.