Sirona S with SensorSafe

The CYBEX Sirona S is the only convertible car seat to feature a 360° rotatable seat with load leg stability, linear side impact protection, and SensorSafe™ technology. *Actual product may vary from product shown, in color and features.
  • Age 0 - 4 yrs
  • Height 49"
  • 4 - 50 lbs.
  • 22 - 65 lbs
Color: Moon Black
In Stock
Was $549.95 , is $399.95
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24.5 in
19 in
25.5 in
30.4 lbs

What is included?

What is included?

  • Sirona S Toddler Car Seat
  • SensorSafe
  • Cup Holder
  • User Guide

Before purchase

Will the Sirona S fit my vehicle?

The Sirona S has been fit tested in a variety of vehicles. Due to variations in vehicle make, models, and years of manufacture, you are encouraged to try the car seat in your vehicle at a retail location nearest you. You should try both rear facing and forward facing modes and in different locations (outboard rear seat, vs middle seat).


Where can I get replacement parts for my product?

You can order replacement parts from our customer service team at ParentLink. Please contact them at or by calling 1-877-242-5676.

How much does the Sirona S weigh?

The weight of the car seat (excluding the infant positioning pillow) is 30.4 lbs.

Does this seat have a cupholder?

Yes this seat comes with 1 cupholder. An additional cupholder may be available to purchase as an accessory. If not available as an accessory, contact ParentLink for spare part information at or by calling 1-877-242-5676.

Installation and Securing your child

Can I also use this seat without the base?

This is a multi-mode car seat and does not feature a detachable base

Where can I check to make sure my car seat is installed properly?

CYBEX recommends getting your car seat installation checked by a Certified Child Passenger Safety Technician. At CYBEX we have certified car seat technicians available to assist you though our customer service team at ParentLink at 1-877-242-5646 or We also have virtual appointments available at

Is it safer to use lower anchors or the vehicle's seat belt?

The safest installation method is the one that allows you to install the car seat correctly. Either method, if used in accordance with the car seat owner's manual and vehicle's owner’s manual requirements, provides protection. The car seat has been tested to meet safety standards installed by either method. Most car seats have lower anchor weight limitations, so please refer to your car seat owner's manual for those specific limitations.

Which installation method is recommended for my Sirona S?

The car seat can be installed with either lower anchors or the vehicle seatbelt. Because of the weight restrictions of the lower anchors, installing with lower anchors for Rear Facing is limited to a child weighing 30 lbs. and Forwad Facing is limited to 35 lbs. Installation of the car seat with the vehicle belt will support the weight of the child from 4-65 lbs. We recommend the use of the seatbelt so you do not need to change the installation method when your child maxes out the lower anchor weight limit.

Can I install the Sirona S using both lower anchors AND the vehicle seat belt?

You can use only either the vehicle seat belt or lower anchors-not both. The Sirona S should be installed using only one installation method.

Can I use the lower anchors in the rear center seat to install my Sirona S?

You should refer to the vehicle owner’s manual for the center seat lower anchor installation. CYBEX allows lower anchor installations of Sirona S in a center seating position if the width of the lower anchor bars in the vehicle is between 11-20” and the vehicle manufacturer also allows. If the vehicle owner’s manual does not specify, or is not clear, it is recommended to contact the vehicle manufacturer for clarity or install the car seat with the vehicle seat belt.

Do I need to use the top tether for forward-facing installation on my Sirona S?

The Sirona S convertible car seat includes a tether for forward-facing use and CYBEX recommends the use of tether when installing a car seat in a forward-facing position if a Tether Anchor is available. The Sirona S innovative load leg feature, however, like a tether, is designed to reduce car seat movement in the event of a crash, so use of the tether is not required in forward-facing mode for this car seat when using the load leg. The Sirona S meets or exceeds applicable U.S. federal safety standards both with and without the tether, and with and without the load leg.

Why is it important to use the tether for forward facing installation?

The use of a tether can reduce the risk of injury by reducing movement of the car seat and the child in certain kinds of crashes. The tether should be used whenever possible for forward-facing installations with either the lower anchors or seat belt. For proper installation, please refer to both the child safety seat manual as well as the vehicle’s owner manual.

Do I have to use the vehicle seat belt installation method for my Sirona S?

The Sirona S allows for the use of lower anchors up to 30 lbs. (13.6kg) for rear-facing mode and 35 lbs. (15.9 kg) in forward-facing mode. However, the vehicle may have additional limitations (Refer to your vehicle owner’s manual typically under Child Restraint or Child Safety in the index). When you can no longer use lower anchors, the Sirona S must be installed using the vehicle’s seat belt. You can also choose to install with the vehicle's seat belt at any time and avoid having to re-install once the child has reached the lower anchor limits. Always use a tether forward-facing if a Tether Anchor is available.

How do I know if I have LATCH available in my vehicle to install the car seat?

Most U.S. vehicles manufactured on or after September 1, 2002, are equipped with LATCH. Refer to your vehicle owner’s manual under the Child Restraints section to confirm and see where your latch connections are.

Where do I store/find my Lower Connectors on my Sirona S?

Storage for Lower Connectors can be found in slots on either side of base. When storing the Lower Connectors, slide each Connector back into its storage slot until an audible click is heard. Easy Lock™ Bar and Belt Tensioner must also be closed. Remove most of the slack from the lower anchor strap by pulling on the lower anchor Adjuster Strap until it lays flat through the Belt Guides. Tuck the excess strap into the vehicle seat crease to get it out of the way.

What is the difference between Rigid Latch vs Flexible Latch?

Flexible lower anchor connectors are connected to each other with flexible webbing. Rigid lower anchor connectors are rigidly attached to the car seat shell or car seat base and there is no flexible webbing. Rigid lower anchor connectors are spaced exactly 11 inches apart to correspond with the standard spacing of lower anchors in the vehicle. CYBEX allows flexible lower anchors to be used with spacing between 11 - 20" apart and given the vehicle manufacturer allows this use.

Safe Travel

What kind of clothing should my child wear when seated in the car seat?

Thick clothing prevents the harness from lying snugly against the body. This incorrect harness use results in a loose or slack harness which in turn reduces the performance of the child restraint in crashes. Also, in everyday use, the loose harness could result in the harness slipping off the child's shoulders. For this reason, your child should wear everyday clothing. Thick clothing, such as puffy jackets, should not be worn in the car seat. In cold weather, after your child has been harnessed in the car seat, their jacket or a blanket can be placed over the child for extra warmth.


Can the car seat be used in a seating position that has a side airbag?

Yes, the car seat can be used in the seating position adjacent to a side airbag unless otherwise indicated in the vehicle owner's manual.

When does my CYBEX Sirona S seat expire?

You can find the date of manufacture and expiration date on a sticker located on the bottom of your Sirona S. Every car seat has an expiration due largely to allow you the benefit of regulatory changes and technology enhancements in child passenger safety. The Sirona S has been certified for 10 years from the date of manufacture. Once your car seat has reached its expiration date, we recommend recycling the seat by contacting your local community recycling center.

Is it ok to keep using my CYBEX car seat after an accident?

We at CYBEX always recommend that you replace child restraint after a crash of any kind, even if it was unoccupied. A crash can cause unseen damage to the child restraint that may not be visible and this damage can pose an increased risk to safety. Your insurance company may be able to provide some assistance in replacing the child restraint. For more info, please reach out to our Customer Service team at ParentLink at or by calling 1-877-242-5676.

When is a child too big for the Sirona S car seat?

The Sirona S car seat is designed for children from 4-65 lbs. with a height between 17" to 49" tall. In addition, you will want to ensure that the top of the child's head is a minimum of 1 inch below the top of the child restraint for rear-facing use. This allows for proper protection in the event of a crash. We recommend you keep your child rear-facing in a convertible or all-in-one seat as long as the seat allows, according to the manufacturer's specifications, before turning them around to ride forward-facing. For this seat that would be 4-50 lbs. for rear-facing and 22 -65 lbs. for forward facing. Please refer to your owner's manual for latch, tether, and recline limitations in each seating position. Children weighing more than 65 lbs. or more than 49" tall should consider a booster seat that accommodates their weight, height, and age.

How long should I keep my child rear facing for?

The head of a young child is large and heavy in proportion to the rest of their body and their neck is relatively weak. A rear-facing child restraint supports the head, neck, and spine, and therefore may help reduce the risk of serious injury. We recommend keeping your child rear facing in a properly installed car seat as long as possible, until they reach the highest weight or maximum height allowed by the seat in the rear-facing position.

Can I used a rolled towel or pool noodle under the base of my car seat to achieve the correct recline angle?

In some vehicles, even when your car seat is in the most reclined position, it may be necessary to place a rolled towel or pool noodle beneath (not behind) the car seat near the vehicle seat back to provide enough recline so that the recline indicator is in the correct zone for rear-facing use. For an infant car seat with the base, the adjustable foot should be stored before adding the rolled towel or pool noodle. For a convertible or all-in-one car seat, make sure the car seat is set in an appropriate rear-facing recline position, and then add the rolled towel or pool noodle. For additional details, please refer to your product instructions or contact our ParentLink customer service team.   

Is it ok if there is a gap between the anti-rebound bar on my infant seat and the back of my vehicle seat?

The most important thing is to get a good installation using either LATCH or the vehicle seat belt.  After properly installing the car seat, check to make sure you have less than 1” of movement at the belt path as indicated in your user manual. As long as you have achieved a tight installation, a small gap between the anti-rebound bar and back of the vehicle seat is acceptable. If your vehicle seat has an adjustable seat back, you may be able to adjust it more upright, which can also help limit the gap between your car seat and vehicle seat.


Are both linear side-impact protectors (L.S.P.s) needed?

The Linear Side-impact Protection (L.S.P.) reduces the forces of a side-impact collision and thus also the risk of injury. For an active L.S.P. you ONLY deploy the L.S.P. towards the vehicle door. You never deploy it towards the center of the vehicle. Also, do not use the L.S.P. when installing the car seat in the middle seat of the vehicle. The only exception to a middle seat installation are boosters where the L.S.P. is in a static or fixed position on the side wings or on an infant seat shell and you don't have to do anything to deploy them.

How big is the Sirona S?

The range of dimensions of the Sirona S are as follows: Rear-facing upright position: 23" H x 21.5" W x 30" D. Forward-Facing upright position: 31" H x 19" W x 28.5" D. The fit in the vehicle and the design of the vehicle seat will impact the dimensions in vehicle.