Cybex Eternis S SensorSafe Car Seat

Updated June 24 2021 By Tom

First into the U.S. baby seat market, the new Cybex Sirona S Convertible Car Seat. Not only that, but it’s also the first of its kind to be approved in North America. Cybex has taken the convertible baby car seat market to a brand new level. 

The Cybex seat, features a leg load stabilizer, revolving 360° centre, changing around from rear face to forwarding face. And, all with one single, comfortable and straightforward action. Also, you’re able to quickly get your child in and out with little to no fuss.

The Sirona S load leg stabilizes the core and may appreciably limit force in crashes. And, combined with an EasyLock bar for swift, secure and effortless installation. Affords the most advanced safety protection for your child with peace of mind that undoubtedly is priceless. 

For instance, a new design feature allows the convertible seat to pivot left or right, giving you much more room to manipulate loading or unloading. Why is that possible? Simply because installing is done through the base, and that allows movement to swing left or right without re-installing.

And, it’s fitted with a Sensorsafe safety clip that alerts you your child’s safely buckled in the seat. Plus, it also draws your attention to the inside car temperature, as to whether it’s too hot or cold. 

Besides, the Sirona S has the same linear side impact protection, that will absorb around 25% of the crash force in the event of a near side-impact collision. The same, impact protection fitted on all Cybex car seats.

A Car Seat Fitted With Many Safety Features 

The new CYBEX Eternis S offers protection that grows with your child, a one only seat required from infant to school-age booster. Such as the rear-facing position from 4 lbs to 50 lbs, with the front-facing, 22 lbs. To 65 lbs. And, a seat belt booster, 40 lbs. To 120 lbs.

Another benefit, the in-seat recline allows your child to ride rear-facing for longer, and safely.

So, the brand will quickly become the all-in-one convertible car seat, designed for use from birth up to 120 lbs and integrated with all the smart, yet And, all in-store in the chest clip of the car seat—the technology, designed to incorporate through a vehicle receiver and or, minders smartphone. Also, the driver receives a warning if, by accident, the child gets left still secured in the car seat. Or, if the child unbuckles the chest clip, whilst the vehicle is in motion.

Includes a patented, three positional reclining headrest.

Designed in a way to prevent the child’s head from falling forward whilst asleep, guiding the head and neck into a safe position. 

And, all combined with a steel-reinforced frame for strength and durability.

Cybex Eternis S SensorSafe Car Seat -  Functions

Seven Advanced Features

In-Seat Recline

Cybex Eternis S SensorSafe Car Seat - In-Seat Recline

The Eternis S, in-seat recline feature, is adjustable to many positions, offers the correct ergonomic positioning, a snugger fit, with extra legroom.

Rear-facing, 4 lbs to 50 lbs, allows your child to ride safely and sleep longer.  

And, will comfortably angle your child’s head to minimize head slump and keep airways open, for a custom, cradled fit.

 Integrated Linear Side-Impact Protection

Cybex Eternis S SensorSafe Car Seat - Intregrated Linear Side-Impact Protection

The sides protection system of the car seat, extend out on both vehicle door sides, thus offering heightened side-impact collision safety protection. 

In the likelihood of a side-impact collision, the system diminishes impact force by around 25%. That’s significant when comparing similar car seat without the extended side intrusions.

Three Positional Reclining Head Rest

Cybex Eternis S SensorSafe Car Seat - Three Positional Reclining Head Rest

The Cybex S reclining headrest has another revolutionary technological patented feature, and, it’s a safety feature long overdue and relates to child head movement and protection in the possibility of a side-impact collision.  

Reduction of head movement is especially crucial in any collision, and this new technology safely moves the child’s head balance point, slightly back, preventing the head from lurching forward when in sleep mode. In contrast, the head remains within the safety zone of the seat. 

And that is a pivotal advancement, ensuring optimal protection of your child’s neck in case of an accidental emergency.  

What’s more, the headrest allows a more comfortable and peaceful sleep, making any journey that much more pleasant. 

Adjustable Head Rest Twelve Position

Cybex Eternis S SensorSafe Car Seat - Adjustable Head Rest Twelve Position

Once your child begins to move up in the seat, there’s no need to reconfigure the harness because the integrated no-rethread harness adjusts with the headrest movement.

As your child continues to grow the twelve positions, a height-adjustable headrest will also grow with your child.

Sensor Safe Technology

With the advanced sensor, safe technology, when unsafe conditions appear, alerts are raised, such as unbuckling your child’s seat belt whilst the vehicle is moving. 

Or, will alert if your child has been in the car seat for a lengthy period and becomes too hot or cold. 

Cybex Eternis S SensorSafe Car Seat - Sensor Safe Technology

And, if the child has been accidentally left unattended in a stationary vehicle. That, in my opinion, has to be the best innovation ever, because it’s something done without realizing it. 

All this is possible using an installed vehicle receiver, connected through a smartphone sensor safe App. Also, the same App has the ability in walking you through the full installation, if required. 

Cybex Eternis S SensorSafe Car Seat - Cup Holder

Cup Holder

Included with the Cybex Eternis S is a removable cup holder that’s locatable on either side of the car seat. Also, the cup is easy to clean or dishwasher safe.  

Cybex Eternis S SensorSafe Car Seat- Effortless Removal

Effortless Removal

Fitted with an advanced one single pull latch removal, making the transition an effortless chore.

Cybex Eternis S SensorSafe Car Seat - Eternis S All-In-One Car Seat



Width, 17.3″

Length, 26.”

Height, 22.25.”

Head Height, 30″

Weight: 25 lbs.

Rear Facing, 0 – 40 lbs.

Weight Capacity: 

Recline: 10 Positional recline


  • In-Seat Recline: correct ergonomic position – snug fit – extra legroom
  • Integrated Linear Side-Impact Protection: heightened side-impact safety protection
  • Three Positional Reclining Headrests: head movement protection from collision impact
  • 12 Position Adjustable Headrest: height adjustments – grows with your child
  • Sensor Safe Technology: Seat unbuckled alert – in-vehicle temperature alert – child unattended in-vehicle alert
  • Cupholder Left or Right: removable cup holder – dishwasher safe
  • Effortless Removal: one single pull latch removal

Final Thoughts

A great car seat, full of all-encompassing safety features imaginable. Parents will most welcome the benefit of the quick and easy installation and removal feature. 

Cybex Eternis S SensorSafe Car Seat - Safety Base

With an anti-rebound design to reduce car seat rebound movement.

Therefore, the car seat, installed through the base, removes the need to undo and reinstall when turning your child around. 

And a one-time vehicle belt installation for both rear-facing and forward-facing mode.

Side impact protection increases your child’s safety in an emergency, adding an extra layer of child protection. 

 Sensorsafe clip alert technology becomes that second backup for parents, especially when the safety belt becomes unbuckled whilst the vehicle is in motion. 

Cybex Eternis S SensorSafe Car Seat - Sensor Clip - Linear Sip Impact Protection

Sirona S is the first convertible car seat, with a 360° rotatable innovative feature. At the same time, the load leg makes switching between rear-facing and forward-facing positions quick and easy.

The Sirona S load leg stabilizes the core and can significantly reduce crash forces.

Combined with an EasyLock™ bar for swift, secure and straightforward installation, offer advanced safety protection for children — and greater peace of mind for parents.

Dual-level indicators help ensure the proper car seat angle.

 Steel reinforced frame for strength and durability with dual-level hands, help ensure the appropriate car seat angle. Plus, 3-position padded buckle and harness pads for extra comfort. And, the removable newborn insert provides support for small babies.

Cybex Eternis S SensorSafe Car Seat - Adjustable Headrest Magnetic Buckle Holders

It’s the car seat with the lot, and, in my opinion, it’s the ultimate choice for parents.

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