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Cybex Eternis S SensorSafe All-in-One Car Seat
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  • 37995
  • Save $ -379.95

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Between its innovative safety technology and ability to grow with your child from birth to 120 pounds, the Cybex Eternis S SensorSafe Convertible Car Seat may be the only car seat your child ever needs.

The Cybex Eternis S is a three-in-one car seat that can be used rear-facing from birth until at least age 2, then forward-facing for an older toddler. But unlike most convertible car seats, the Eternis S then transforms into a belt-positioning booster seat that your child can use until graduating from car seats altogether.

The chest clip of the Eternis S features SensorSafe technology, which alerts parents to potentially unsafe situations. Using a vehicle receiver and smartphone app, SensorSafe notifies parents if they have accidentally left a child behind in the car, if the car is becoming too hot or too cold, if the child has unbuckled their chest clip, and other important situations.

The steel-reinforced Eternis S also features the Cybex linear side impact protection pods that extend from the side of the seat, which the manufacturer says absorbs 25 percent more crash forces in the event of a side-impact crash.

In another unique feature, the headrest of the Eternis S reclines to three positions, ensuring a comfortable and safe head position for naps on the go. The headrest tilts the child's head slightly back to prevent it from falling forward, while keeping the head within the seat's safety zone.

Additional features like a 6-position recline, 12-position headrest with no-rethread harness and an included cup holder make the Eternis S easy to use, no matter the age of your child.


Car Seat Features

  • Transforms from rear-facing to forward-facing convertible car seat and then to a booster seat, accommodating children from birth all the way to 120 pounds
  • Designed in Germany with steel-reinforced shell
  • Reclines with one hand to 6 positions
  • Patented 3-position headrest provides comfort and prevents child's head from falling forward out of the headrest safety zone
  • Linear Side Impact Protection System pods on the side of seat help absorb up to 25% more impact forces in a side-impact crash
  • 12-position adjustable headrest with integrated no-rethread harness make for easier adjustments as your child grows
  • One-pull LATCH connector removal for easy installations
  • Fabric covers are machine-washable
  • Includes SensorSafe technology in the chest clip (see next section)

SensorSafe Features

  • Chimes if child is still secured in seat when car is turned off
  • Alerts caregiver's cell phone if child is left behind in vehicle and then, if situation is not remedied, alerts designated emergency contact
  • Emergency contact receives GPS coordinates of vehicle's last known position
  • Monitors back seat temperature to alert vehicle receiver and caregiver's phone if car appears to be too hot or too cold
  • Provides alerts to caregiver when child may have been seated for too long
  • Receiver plugs into car's OBD port and syncs with caregiver's cell phone
  • App available for iOS and Android


  • Rear-facing specifications: 4 to 50 pounds; suggested for children up to at least 2 years
  • Forward-facing specifications: 22 to 65 pounds
  • Booster specifications: 40 to 120 pounds; up to 57" height
  • Dimensions: 25.3" L x 20" W x 25.5" H
  • Product weight: 26 pounds

What's Included

  • Cybex Eternis S SensorSafe Convertible Car Seat
  • Cup Holder