Review: Cybex Sirona S Convertible Car Seat

As a parent, I've found most baby-centric technology to be pretty clunky. From bulky baby monitors to unwieldy strollers, there just isn't as much innovation as I hoped for back when I was pregnant. Car seats fall into this category, too, with layers of cushions that are just begging for juice stains and Cheerios to be lost in them, and ugly block colors that were invented specifically to irritate me.

Car seats aren't really just for looking great, obviously. They're for safely transporting your child in the car and keeping them safe in the case of an accident. But what I like about the Cybex Sirona S is that it's not only a little easier on the eyes, but it has a few forward-thinking features, including a smart, Bluetooth-powered buckle on it that makes sure your child isn't left alone in the car.

Leaving your kid in a car unattended can result in a hot car death. When I told one parent about testing this kind of technology, they scoffed and talked about how rare these instances are, and how parents should just be more careful. While it is rare—Kids and Car Safety reported 36 deaths in the US last year—it easily could happen to any parent, and could just as easily be prevented with a little help from technology.

Photograph: Cybex

The most impressive thing about this car seat isn't the seat itself, but the powerful little buckle on it. The SensorSafe buckle is lightweight and discreet, and you'd only know it was a Bluetooth device by the little light-up symbol on it. It can track when the buckle is open or closed, how far away your phone is from the buckle itself, and the temperature in your car.

SensorSafe is a separate company, and it partners with both Cybex and Evenflo to make car seats that use its buckle. Each company then makes its own app to pair with the device. The Cybex app is very clean and minimalist. After plugging in which car seat I'm using and connecting it via Bluetooth to my phone, the app's main page shows nothing but whether the car seat is online, the temperature in the car (which it can only read if online), and a list of my devices. You can add several Cybex devices into the same app and see them all there, or just the one car seat like I had. You'll also be prompted to invite family members as emergency contacts if your child is left behind in the car.

The app also has a tab for manuals. It lists the car seats you're using, per what you've told the app, at the top, then manuals to a few different generations of SensorSafe, plus manuals to other Cybex car seat models at the very bottom in case you're feeling like browsing. I tested the SensorSafe 3, which differs from past models because it doesn't need a receiver plugged into your car to connect to your phone. There is a version with a dongle, but I tested the clip-only version. If you have a dongle model, read Adrienne So's review of the Evenflo Gold, where she talks about plugging the receiver into her car's ODB-II port.

But even without a dongle to plug into your computer, this car seat is a bit of an installation project. You need to face it backwards to reveal the belt path, which was easy enough, but my husband and I didn't find the locking system intuitive to open up on our own without watching a video (this one is great). It took a few tries to open the locking system, but afterwards it was easy to lock the seat belt in place.

The Sirona S also uses a load leg, which intimidated me a little, but it was easier to use than the belt locking system (at least for us). It was easy to adjust the leg and look for the green locking symbol on the base. We wiggled it around and adjusted it a few times to get the perfect height set.

Photograph: Cybex

This isn't the first car seat sensor device I've tested. The Doona Smart Cushion worked well, but I found the sounds to be much more irritating, and found that it was easy to set off the weight sensor without actually having my child in the car. I still hear the beeping of the device when it randomly reactivates on my gear shelf.

In comparison to the incessant beeping of the Doona, the double chime of the Cybex is downright lovely. Two chimes go off to alert you when you leave your child in the car (or, in my case, leave the buckle buckled while no one is in said car and wander away from it) and to alert you if the car gets too hot. Both my phone and buckle went off. Though such a nice-sounding chime does have its downsides: My husband thought the car next to us “must have been playing music or something” since it didn't sound like an immediate problem alert to him. In contrast, he always knew the Doona was trying to tell him something—and he hated it.

Once I was familiar with the chimes, though, it was quick for me to know that was the Cybex trying to talk to me. Once you're 25 feet away from the car, an alert goes off to tell you you've left your child behind, and a two-minute countdown is started. After two minutes, it will alert you again, warning you it will call the family members you designated as emergency contacts soon. If you ignore that alert, designated family contacts will get a notification with the location of your child and the car seat they're sitting in.

The car seat will also chime if the temperature is above 95 degrees Fahrenheit (35 degrees Celsius) or below 35 degrees Fahrenheit (2 degrees Celsius). I was shocked that the car seat alerted me that it was too cold in the car on a chilly December morning, since I live in Southern California, but it was a nice reminder that you can't assume anything about temperatures these days. I was a little disappointed that, unlike the Doona, the Cybex doesn't call your phone and yell at you in a robot voice if your kid has been left alone in the car for several minutes. I liked that!

My favorite futuristic feature, though, is the 360-degree rotation. It doesn't really work with a single hand like Cybex says, however—I usually needed both hands to get the leverage to release the rotation, and to lock it back in place.

But even with the constant resistance it gives me when I rotate the car seat, I love it. Why do I love it? I have no idea. Is it because it feels straight out of The Jetsons? Is it because I can rotate it for better leverage on buckling my wriggling toddler? Is it because even though my child is nowhere near ready to face forward, I know I'll be able to switch his position in a split second? Is it because I wish he could face forward so that the sun would stop blasting him in the eyes?

Maybe it's all of these things. Between the Bluetooth buckle and the full rotation, this car seat feels like a step forward in a way that plenty of baby gear lacks, without going overboard on features we don't need. It feels simple and streamlined, focused on features I actually want: keeping my child safe in the car, whether it be from other cars, hot temperatures, or my own potential forgetfulness.

Too bad the price tag is so steep. It's as much as a stroller, and twice as much as your regular convertible car seat. Evenflo has much cheaper models that include SensorSafe (though the buckle on these car seats looks like older models that will require a dongle). If only I could send the bill to future me; I'm sure she could spare it after buying her flying car, right?