We’ve enjoyed following the Cybex Aton line of rear facing only seats as it’s evolved, from the original Aton to the Aton 2 and Aton Q. (If you read these, you’ll notice our review style has evolved as well!) And now, there’s a new Aton on the block, with a brand new base and some variations on Cybex’s unique features. Meet the Cybex Aton M.
CSFTL Quick Stats
- Weight range: 4-35 pounds
- Lowest Harness Position: about 8 inches with infant insert
- Height Range: 17-30 inches and the top of the child’s head is 1 inch or more from the top of the headrest
- Expiration: 6 years from date of manufacture
- Handle Position: Must be in “position A”, upright, in vehicle
- Shell Height: 20 inches with headrest fully extended
- Weight (carrier only): 10.5 pounds
- Width at widest point: 17 inches (carrier)
- Width of base: 16 inches
- Front to back, installed with base: 27 inches (measurement may vary with angle of vehicle seatback)
SafeLock™ Base with Anti Rebound Design and Load Leg
The Aton M base features a lockoff panel that closes over the lower anchor webbing or the vehicle seat belt. The part of the base near the back of the car has an anti-rebound design, and the other end of the base features a load leg, which limits downward rotation and adds stability.
Integrated Linear Side-Impact Protection (L.S.P.) System
Like the other Atons in Cybex’s rear facing only car seat product line, the Aton M has a linear side impact protection device on either side of the carrier portion of the seat that must be extended once the carrier is in the base. The L.S.P. should be extended on the side of the car seat that’s closest to the vehicle’s door. It’s not used when the Aton M is installed in the vehicle’s center seat.
No Rethread Harness
The Aton M features a no rethread harness. The harness strap height and the headrest adjust at the same time when the headrest moves up or down. To raise and lower the headrest and harness, pull up on a plastic piece inside the back of the headrest.
Integrated XXL Foldaway Sun Canopy
The Aton M has a huge canopy that extends easily and retracts smoothly. While canopies aren’t a safety feature, we know they’re important to some families. (Always make sure there is adequate air circulation in front of the baby!) The canopy is an area where the Aton M has a lot to offer!
With the Base
The Aton M arrives with the lower anchors stored on the side of the base.
Here’s how to get it set up for installation:
Pull the red loop on the end of the lower anchors to release them from the base. This may not be obvious to caregivers who aren’t familiar with this specific style of lower anchor connectors.
Next, unfold the load leg from the bottom of the base. Note: unfolding the load leg was not easy — I had to squeeze pretty hard to extract it from the bottom of the base. UPDATE: Cybex has told us they’ll be making a change so that it’s easier to unfold the load leg from the bottom of the base.
Once the lower anchors are removed and the load leg is extended, place the base on the vehicle seat and adjust the recline using the handle on the part of the base near the back of the vehicle. The Aton M has an easy to understand red or green recline angle indicator. Unlike the recline angle indicators on the other Aton car seats, there are not separate ranges for different weights.
After the base is set up on the vehicle seat, use the button on the load leg to extend the load leg to the floor. We had some trouble with the load leg that we’ll explain later in this review.
The next step is to open the lockoff, then connect the lower anchors to the vehicle. I found that opening the lockoff was more difficult than I expected; there’s no real place to grip the lockoff to get it open. You have to dig your fingers in and press very hard to get it open.
When the lockoff is open, tighten the lower anchor webbing. Be sure to pull all of the slack in the webbing over to the adjuster side before tightening — the slack tends to get caught on the other side.
The Aton M differs from the other Cybex seats in that the lockoff is able to close over a taut lower anchor webbing. There doesn’t seem to be any need to leave it a bit loose in order to close the lockoff.
To complete the installation, lower the lockoff and squeeze the handle to close it. This is a different type of lockoff closure than the “slam the door” style lockoffs found on the Britax ClickTight car seats, for example.
We found a rather unique issue that we’d like to share.
One of the vehicles in which we installed the Aton M has relatively flat vehicle seats and lower anchors that are mounted higher than we typically see. This spacing meant that the lower anchor connectors are so long that they take up the entire space between the belt path and the anchors themselves. In this type of vehicle, we found it almost impossible to install the base securely with the lower anchors.
This is the same lower anchor issue that we found with the Cybex Sirona M. Thankfully in this case, there is an easy solution: install the base with the vehicle seat belt instead.
UPDATE: Cybex has told us they’ll be changing the lower anchor system on the Aton M base to ensure the base can be installed tightly even in a vehicle with raised or prominent lower anchors.
Load Leg Difficulties
There are two indicators at the top of the load leg. One shows whether the carrier is clicked into the base, and the other shows whether the load leg is locked into position.It took me a few tries to realize that the load leg is only locked into position when it’s extended at an angle towards the front of the vehicle. That is, the bottom of the load leg is closer to the front of the vehicle than the top is. It’s necessary to give the load leg a VERY firm tug towards the front of the car to put it in the correct position.
The bottom of the load leg has two tiny red indicators that turn green when the load leg is firmly in place.
We had some challenges with these indicators. If the load leg is extended correctly, there is often not enough pressure on the bottom of the load leg to turn the indicator green. Extending the load leg another click only lifts the base off the vehicle seat, which is not allowed.
Cybex has confirmed for us that as long as the load leg indicator is green when the seat is on the base and a baby is in the seat, it may be used even if it is red when the seat is not on the base.
Vehicle Seat Belt
Right off the bat, we’d like to mention an error in the manual from the vehicle seat belt installation of the base section. The manual implies that the vehicle seat belt must be locked, but it does not. Unlike other Cybex rear facing only car seats, the Aton M base features a true lockoff. Cybex will be updating this section of the manual.
To install the base with the vehicle seat belt, adjust the recline foot and load leg as indicated in the lower anchor section above. Open the lockoff. Thread both the lap and shoulder portions of the seat belt through the blue belt guides. Remove all slack and close the lockoff by squeezing the release handle. I found the seat belt installation on the Aton M to be much easier than the lower anchor installation.
The Aton M may touch the vehicle seat in front of it as long as the carrier clicks into the base correctly and the recline angle is not affected.
Installation Without the Base
The Aton M features baseless European routing. Cybex recommends this method for baseless installations. The blue belt guides on the sides of the carrier and on the back of the carrier are easy to access, although the shoulder belt guide on the back of the carrier is not labeled.
To install the carrier with European routing, extend the L.S.P on the side near the door, unless the seat is being installed in the middle. Next, thread the lap portion of the belt through the blue belt guides on the sides of the carrier.
Buckle the vehicle seat belt, then thread the shoulder belt around the back of the seat and thread it through the blue belt guide.
If the vehicle seat belt hasn’t locked itself already by this point — sometimes that happens with a longer routing that uses up more of the vehicle seat belt — lock the belt by pulling it all the way out from the point where it’s mounted in the car until it locks in place. Remove all the slack from the vehicle seat belt by pulling the shoulder belt and feeding the slack back in toward the vehicle to tighten the installation.
Last of all, check the red recline angle level line on the side of the seat to make sure the seat is at the correct angle, and adjust as necessary.
The Aton M also allows American belt routing, where the lap portion of the belt is buckled through the blue belt guides, but the shoulder belt is not wrapped around the back of the carrier. The Aton M carrier is very compact, so European routing should be possible in many vehicles.
Removing the Carrier from the Base
The Aton M has a two step system to remove the carrier from the base. First, press down on a smaller white button on top of the base, near the load leg, then press a larger white button that’s perpendicular to the first button.
This was pretty challenging because I couldn’t quite press the smaller button with my thumb. I had some success with using the knuckle of my index finger to press the smaller button, then using my thumb to press the larger button.
The Aton M base has instructions on the base that explain how to use these buttons, but unfortunately this guide is invisible when the carrier is clicked onto the base.
Fit to Child
The Aton M infant insert is required for babies who weigh less than 11 pounds. It should be positioned so that the cut out part is against the buckle.We checked with Cybex, and they told us that the insert can be left in past 11 pounds if the fit is improved with it. We found that it helps the fit to leave it in as long as is comfortable for the baby.
I tried three babies under 7 pounds in the Aton M, and unfortunately the straps were not at or below the shoulders on any of them. I shared this with Cybex, and they told us they’ll be redoing the infant fit, either by adding a foam inlay under the insert, or beefing up the insert. We look forward to these changes!
This little princess was born 5 weeks early, and she’s now 6 weeks old. She’s 6 pounds 6 ounces, and she’s 19 inches tall. We can see that the straps are not at or below her shoulders, so she cannot travel safely yet in the Aton M.
This young man was all of 48 hours old at the time of this picture! He’s 7 pounds 11 ounces and 21 inches tall. He fit well in the Aton M with the insert.
This big little guy was almost 2 months old at the time of this picture. He’s just over 11 pounds and about 22 inches. We tried him with and without the insert. With the insert, he fit beautifully in the Aton M. However, we can see that the sides of the crotch buckle will eventually dig into his thighs.
Without the insert, he has some head slump, and his positioning isn’t ideal.
10 Month Old
This cutie is 10 months old. He’s 30 inches tall and 19 pounds. Since the Aton M can be used for babies 30 inches and less, we tried him in this seat. He was not that comfortable — the Aton M headrest has a slight downward angle which pushed his chin down and made him a bit crunched.
However, there’s a more important issue. The Aton M headrest is relatively short top to bottom, which means that for older babies, when the straps are at or below the shoulders, the baby’s head will already be near the top of the headrest. The seat is outgrown when the head is less than 1 inch from the top of the headrest. As we can see in these photos, this baby has already outgrown the Aton M at 10 months.
Cleaning: Here Comes the Sun
We noticed a unique cleaning instruction on the Aton M: “Never leave the cover to dry in strong sunlight.” We knew we needed to ask Cybex about this, as that’s one of our go-to solutions for freshening up stinky seats. We are happy to report that Cybex informed us that this is just to prevent discoloration. Phew! A faded yet freshened-up seat is a tradeoff we can live with.
Important Information: Where to Find
The Aton M Carrier is certified for use on aircraft, but the base is not. The FAA approval wording is clearly written in red on a label on the underside of the carrier.
Date of Manufacture Label
The Aton M expires 6 years after the date of manufacture. This is clearly indicated on a label on the underside of the carrier.
The Aton M manual is stored in a slot on the back of the carrier.
The Aton M is a stylish plush addition to the Cybex lineup. With its large canopy and seamless baseless installation, it may be a great choice for city-dwellers who often install their seats in various vehicles. We wish the headrest were a bit bigger, so that babies closer to the 30 inch limit could use the seat. Also, at this point we cannot recommend it for newborns under 7 pounds. We look forward to seeing what updates Cybex makes to the Aton M in the future!