That viral phrase, ‘I don’t have a favorite kid, but there is one we try really hard not to annoy,’ perfectly fits my rowdy three-nager. She’s unabashedly commandeering yet sweet, always getting away with mischief. She’s tossed our car keys in the trash can and now runs to bust open the front door and welcome visitors whenever she hears the doorbell ring (sorry, UPS guy).

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We discipline her plenty, but know we’re the biggest culprits for her brazenness, being the baby of the family. Giving her control over small things helps her stay confident without tipping into chaos. I taught her how to talk to Alexa to control music and lights and, more recently, how to peer into the front door camera with the Eufy FamiLock S3 Max, which has proven quite effective.

The Eufy Security FamiLock S3 Max was designed to be a family-friendly smart lock, hence the FamiLock branding. This lock uses palm-vein recognition for unlocking, a biometric scanning technology that is more accurate than fingerprint scans, passcodes, app unlocking, and a physical key. 

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On the inside, the smart lock features a display that shows what is happening outside your door in real time. This is perfect for kids, visitors, and other family members who may not have access to the Eufy app to see motion alerts.

When the doorbell rings now, my kids run to the front door and look at the display instead of my three-year-old running to swing the front door open (yes, I already bought an extra child-proof lock). Now, she looks at the lock’s display to satisfy her curiosity and runs to tell us whether the ‘box truck guy’ has a box. 

Thanks to the built-in camera and accompanying doorbell button, the FamiLock S3 Max also functions as a video doorbell. This is perfect if you live somewhere with doorbell restrictions, as some rentals don’t allow video doorbells, or if you just want a 2-in-1 solution. 

The best part? The Eufy FamiLock S3 Max is subscription-free if you add a Eufy HomeBase 3 for local storage. The HomeBase can also function as a doorbell chime and a security alarm for the Eufy Security system. 

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But the HomeBase 3’s biggest power is AI-powered facial recognition. It accurately identifies people in your household to tell you exactly who is at the door, whether it’s ‘Dad’ or a stranger. I only wish the HomeBase 3 and FamiLock S3 Max could combine this feature to unlock the door when a known and authorized person is detected. 

I’m constantly testing smart locks, which means that my family always has to adjust to a new door lock on the fly. Though I try to keep similar passcodes when switching smart locks, the constant change means losing saved fingerprint data, which makes it harder for my kids to unlock the door. 

But many of the smart locks with fingerprint scanners I’ve tested have been finicky and unreliable, with the glaring exception of the Lockly Visage Zeno Series, so I was eager to test palm vein recognition.

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Palm vein recognition is considered a more accurate biometric screening than fingerprint scanning. The veins in your palm are far less likely to change over time, unlike fingerprints, which are susceptible to changes in your skin and can be temporarily affected by something as simple as dry winter skin. 

Setting up the palm vein recognition is also much quicker than fingerprints, as fast as taking a snapshot of your hand. Unlocking the door with my palm has been a smooth process this weekend, but I’ll test all of the FamiLock S3 Max’s features over the coming weeks before the smart lock’s general release.

ZDNET’s buying advice

Testing the Eufy FamiLock S3 Max has been an easy and convenient experience thus far. This smart lock is perfect for new and existing Eufy Security customers, especially if you have the HomeBase 3 to bypass monthly subscription fees and enjoy facial recognition alerts. It’s easy to install and has proven itself to be reliable and responsive, never losing connectivity and consistently unlocking and locking when prompted.

The only drawbacks to this smart lock are that your view is obstructed if you have a screen or storm door in front of your front door, as I do, the fact that it doesn’t unlock with facial recognition, and it is very expensive, though you can get one without an interior display for $50 less.