Cybex Eternis S SensorSafe All-in-One Car Seat



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

Shipping Information

Most orders are shipped via FedEx Ground from our warehouse in Scottsdale, Arizona within 1 business day.

In some cases, Strolleria will dropship an order directly from the manufacturer to the customer to shorten the delivery time. In these instances, items typically ship within three business days, but the total delivery time is reduced.

Please see this page for the number of days it takes for products shipped via FedEx Ground from Scottsdale to arrive at your location. FedEx delivers packages on Saturdays and Sundays in most cities, excluding rural areas.

Return Policy

Strolleria accepts returns of new, unused items that are returned to us within 60 days of receipt. 

Because safety is a top priority for us and all new parents, Strolleria only accepts returns of items that have never been used. Items must be returned in the same condition in which you received them, including the original packaging.

All products sold by Strolleria are covered under a manufacturer's warranty. If the product is defective or becomes damaged during the warranty period, the manufacturer will send a repair or replacement part at no cost.

Visit this page for our complete return policy.


Customer Reviews

Based on 3 reviews
Awful carseat

I own 6 different carseat brands--- this is by far the worst. We bought this seat for grandma's car. Buckles are impossible to unbuckle. We can hardly unclip them, grandma (who is healthy and in shape) is unable to use this seat.

Very well made

I Checked this at Dillard's. It is very high quality. Though a bit pricy for me. It has extra cusion/pad for smaller babies—very soft fabric.

Very much satisfied

Great quality brand. Highly recommend.