Sirona M vs Sirona S

Cybex is one of the most advanced car safety seats made for small children until they are ready to use the seat belt with the booster. For the smaller kids who are rapidly growing up and concerned parents, Sirona M Vs Sirona s are two promising options from the collection. The two are built with safety sensors for monitoring the passenger condition when necessary and if parents also wonder which to go for, let’s see what the two can offer here.

In this comparison, we are going to talk about:

  • Which Seat to Buy
  • What are Sirona M and Sirona S
  • How are the Design of Sirona M and Sirona S
  • How are the Installation of Sirona M and Sirona S
  • How are the Fitting of Sirona M and Sirona S
  • What else Sirona M and Sirona S can offer
  • Sirona M Vs Sirona S

Buying a Car Safety Seat 

Being a parent means we are worrying all the time about our little one because it is just the nature for us to give a safe environment and provide for their overall wellbeing. We want them to grow healthily and happily but there are so many factors beyond our control. The road for example is not the safest place to be but we need to be there when travelling and accessing various facilities as well as getting the supply for the household.

Parents and the older siblings who are already tall enough to use a seat belt must be buckled all the time while traveling in the vehicle but our little kids are not yet allowed to use only the seatbelt. They will need a safety seat to mimic the function of the seatbelt but also provide more protection. Safety seats are available in various types depending on the height and weight of the kid. It starts with an infant car seat and ends with a booster seat with a convertible seat like Clek Foonf vs Diono in between.

When buying a safety seat, unless it is for the first time and for an infant, what parents must know is the height and weight of the kid. To work properly each car seat has their own weight and height limit that the seat can cover when facing an impact. If you bring the kid while shopping, let them try the seat first and as a rule of thumb, make sure that the tip of the seat is at least 1 inch taller than the head.

Typically, a convertible car seat is used after the infant car seat which is from at least 5 lbs. for most seats or less than 20 lbs. when the car seat is installed in the rear part or up to 40 and 50 lbs. when used in front facing. The last car seat is a booster which is used after the kid is growing out of the convertible or front facing seat. Depending on the law in your place, kids as old as 9 years old and weighing at 80 lbs. mostly required to use the booster.

If this is not the first car seat, as long as the safety seat is not facing any impact or in an accident before, they will still be useful for the younger siblings. But, they do expire and make sure to know when the car is manufactured or when the date of expiration is because we want to avoid using car seats that are no longer reliable or updated to the current safety requirement.

 Sirona MSirona S
Product Dimensions‎29 x 20 x 18.5 inches
‎25.3 x 20 x 25.5 inches
Shipping Weight‎5 Pounds
‎4 Pounds
Best offerCheck priceCheck price

About Sirona M and Sirona S

Now when parents are ready to find the car seat, whether it is the first or next step into the journey, it is time to see what the market has to offer because there are so many of them. Car seats must be made to meet or exceed the Federal requirement to be safely designed and sustain the impact. On the other hand they can also be made with additional safety features or much improved crash performance depending on how the company created it.

For parents who are concerned about the kid’s safety in their safety seat, Cybex is a great option to consider. This brand is making various car seats for almost every life stage until they are ready to leave the booster seat. Price wise they are rather pricey however, so it may not be as versatile for most parents. What we love the most from their safety seats is the sensors which are rarely seen on most seats and this can be helpful for monitoring their safety.

Just like most brands, you will find more than one or two seats from this company and this can be a bit confusing for a quick shop since while they may look similar, there must be some differences as well such as the Sirona M and Sirona S from Cybex. These seats are similar in terms of the safety sensors they come with but different on the system that surround and build the seat. In comparison the Sirona S will be the more advanced seat.

But, it doesn’t mean the M variant is a bad option because it is completely a solid system as well. In our opinion parents who want the best convenience may want to try the Sirona S while if the feature doesn’t seem as interesting then we can save a lot with Sirona M. Our personal favorite from Sirona M and Sirona S is actually their ease of use because many other seats especially convertible are stressful to install.

Sirona M and Sirona S Design

These seats have solid built and as you can see, they are different from many other budget options by being made with a simpler look but gives off this elegant styling. Upon seeing the Sirona S our mind instantly thinks of it as a “pod” because of the rounded shape. It is noticeably different from the Sirona M on the base because this seat has a very unique installation and in addition a foot that supports the base above the car’s flooring.

On the other hand, the Sirona M looks more common with a square base but the actual seat itself is the same as the Sirona S. The seats are looking very streamlined but they are not compact at all as the largest measurement on width is at 21 inches. As you can expect, the Sirona S will be the heavier seat in comparison but this model is expiring in 10 years instead of the Sirona M at 8 years.

Sirona M and Sirona S Installation 

Now for the most important part, let’s see what Sirona M and Sirona S can offer to you starting with the installation convenience. Both of them are relying on lower anchors in which the connector looks different from each other. It is not the simple hook we are used to but with a bigger connector which makes the installation simpler, especially convenient as they have this loop to detach the connector quickly. You can add top tether as well but this is an extra step for forward facing only.

The concerning part is probably because the Sirona S has a fixed base with a rotating seat so parents may confuse how the top tether works in front facing since it means we have to attach and detach it from time to time which defeats the purpose of this rotating system. It seems the load leg is designed to handle this issue but many parents seem to have problems with how this seat is securely installed while on the other hand Sirona M is simpler, even without the rotating feature.

Sirona M and Sirona S Fitting

Next is for the fitting but as most car seats, the Sirona M and Sirona S are very much the same with the front facing is meant for when the kid is less than 40 or 50 lbs. respectively while the front facing can be used since they are at least 22 lbs. The age may vary depending on how fast the kid grows but to fit properly in the seat harness, they must be 49 inches tall or shorter as this is the highest the harness can go.

Sirona M and Sirona S Features

Additionally, the seats are coming with some features and the most interesting part is their SensorSafe. This is located at the chest strap of the seat and a receiver on the vehicle’s OBD port. There is an app to accompany the sensor so the caregiver will get notified with some critical alerts or to remind them when the kid is left too long or when the temperature is too hot in the vehicle. The two also have side impact protection.

It is in different shape or design on both Sirona M and Sirona S but they have the same function. It can be extended to enhance the seat’s dimension or to cover the side point near the door. Additionally, the Sirona S has a built-in bumper bar which is one with the base itself.

Sirona M vs Sirona S

Both car seats are very useful and interesting yet arguably the Sirona S comes with more to offer, especially when it has this rotating system that is convenient for loading and unloading the passenger. The top tether is probably a bit concerning because we need to use this in forward position but the load leg can be helpful in case you don’t want to use the tether. Installation is equally simple on both seats if you choose the lower anchor while seatbelt on Sirona M require more work.

- Cybex exclusive SensorSafe 2.0 Technology integrated into the 5-point safety harness chest clip, syncs with vehicle receiver and caregiver cellphone to provide alerts to the child's wellbeing.Care & Cleaning: Spot or Wipe Clean
- LSP (Linear Side-impact Protection) System and energy absorbing shell helps reduce the forces felt by your child in the event a collision
- One-pull LATCH removal system
- 12-position, easy-adjust headrest with integrated harness system grows with your child to keep them protected
- EasyLock Bar: Reduces the force needed up to 4x for simple and secure car seat installation. Dual-level indicators ensure that your car seat is at the correct recline angle while our load leg can reduce rotation in certain crashes by up to 30%.
- SensorSafe: Built into the chest clip, SensorSafe provides app alerts if a child unbuckles themselves; if the back seat has become too warm or too cold, if a child has been seated for too long, or if the driver accidentally leaves the child behind.
- Superior Protection: Linear side-impact protection (L.S.P.) absorbs up to 25% more impact in a collision compared to the same car seat without L.S.P. extended while the anti-rebound design reduces car seat rebound movement in the event of a crash.
- Adjustable Headrest: Make sure your car seat is always a perfect fit with 12 different headrest positions. The Sirona S harness adjusts without re-threading, making it easier to adjust the height of the shoulder straps as your child grows.


You can go amazing with any of the seats because there is no bad option here and both equally have the SafeSensor for necessary alerts. But, personally we will recommend the Sirona M if you will be using the tether because it is more affordable and equally safe with less to fiddle with.