Eternis S
for children 4-120 lbs. / birth to approximately 10 years old

Eternis S

In Stock



The CYBEX Eternis S with SensorSafe All-In-One Car Seat offers 10 years of use in one easy-to-use package – making it the only car seat your child will need, from birth and beyond. The SensorSafe technology integrates important next-gen safety features into the chest clip of the car seat to alert you when unsafe situations arise.

The Eternis S offers an adjustable Linear Side-impact Protection (L.S.P. System), which absorbs up to 25% more impact forces in the event of a side impact collision* and a patented 3-position reclining headrest, which helps prevent the child's head from falling forward while asleep, guiding the head and neck into a safe position. These features, combined with a steel reinforced frame for strength and durability provide advanced child safety protection and peace of mind.

Suitable from 4 lbs. up to 120 lbs., the Eternis S offers 3 stages of protection – as a rear-facing infant seat up to 50 lbs., a forward facing convertible seat and then as a belt-positioning booster that lasts through your child’s first 10 years of age. 

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Expiration: 10 years

Returns: 30 days


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Why You’ll Love it

The Eternis S with SensorSafe monitors the well-being of the seated child through the smart chest clip that is synced with the installed vehicle receiver and the caregiver's smartphone; and while originally developed to help prevent the rising number of infant hot car deaths, the Cybex design of this technology has been expanded to ensure safety for children in a range of additional situations.

The Eternis S with SensorSafe still provides that essential alert when the caregiver accidentally leaves the child behind in the car, but also alerts the caregiver if a child unbuckles themselves while the vehicle is in motion; if the back seat has become too warm or too cold; and if a child has been seated for too long —all through a user-friendly app, that also provides guidance on installation, how-to videos, FAQ’s and other useful information to help prevent car seat misuse.

  • 5-point safety harness with SensorSafe Technology integrated in the chest clip
  • 12-Position Adjustable Headrest offers comfortable protection as your child grows. The integrated no-rethread harness adjusts with the headrest movement so there’s no need to reconfigure the harness as your child moves up in the seat.
  • Adjustable Linear Side-impact Protection (L.S.P. System) absorbs up to 25% more impact forces in the event of a side impact.*
  • Energy Absorbing Shell to help reduce the forces felt by the child in a collision.
  • Magnetic Buckle Holder for easy entry and exit from the seat.
  • 10-position one-hand adjustable recline helps ensure proper angling and best fit to your vehicle seat.
  • Removable newborn inlay provides additional support for babies from 4 lbs. to 11 lbs.
  • The removable cup holder can be positioned on either side and is dishwasher safe for easy clean up.
  • Innovative one-pull LATCH removal system for easy transitions.
  • 2 Year Warranty
  • Engineered in Germany
  • SensorSafe Technology available on select models ONLY
  • SensorSafe is compatible with most vehicles 2008 or newer with an OBD II port. For some electric vehicles, contact Parentlink as an additional adapter may be needed

*when compared to the same car seat without L.S.P. extended

Product Details

Child Specs (4-120lbs)


  • Weight: 4 - 50 lbs
  • Height: 17 - 48 inches
  • Fit: Top of head must be at least 1" below top of headrest. Harness at or below shoulders.


  • Weight: 22 - 65 lbs
  • Height: 28 - 49 inches
  • Age: For children at least 2 years old
  • Fit: The tops of child's ears are below the top of the child restraint headrest.


  • Weight: 33 - 120 lbs
  • Height: 44 - 57 inches
  • Age: For children at least 3 years old
  • Fit: Recommended for children who exceeds the weight or height limits of Forward-Facing Harnessed mode or weighs at least 33 lbs (3+ years).

Product & Shipping Specs

  • Dimensions: Rear-Facing H 19" x W 22-25" x D 32" Forward-Facing (Fully upright) H 25.5-29.5" x W 19.75-22” x D 25.25”
  • Product Weight: 26 lbs.
  • Package Width: Rear-Facing: 22-25" Forward-Facing: 19.75-22” (PKG: 20.4")
  • Package Weight: PKG: 29.5 lbs
  • Package Depth: Rear-Facing: 32" Forward-Facing: 25.25” (PKG: 23.4")
  • Package Height: Rear-Facing: 19" Forward-Facing (Fully upright): 25.5-29.5" (PKG: 26.3")