Cybex Sirona Si i-Size Car Seat (3 Months–4.5 Years) with integrated base
€469.95
This product will be released on 31 December 2026
- Rear-facing safety: Up to 50% better protection for your child
- 360° rotation: Lift your little one in with less back strain
- Base S included: Enjoy an easy start from the first ride
- GrowTech comfort: Support that adapts as your child grows
- Side-impact protection: L.S.P. reduces forces by up to 25%
- Easy-In harness: Buckle up faster with less fuss each day
Description
Cybex Sirona Si i-Size: Safe on Every Journey
Do you want to provide your child with the highest level of safety and comfort on every car journey? The Cybex Sirona Si i-Size car seat (61–105 cm) with included base accompanies your little one from approximately 3 months up to 4.5 years of age (max. 20 kg). Thanks to its rear-facing seating position, it offers up to 50% better protection in a frontal impact compared to the same seat in a forward-facing position. The energy-absorbing seat shell surrounds your child like a protective cocoon and distributes impact forces effectively. With optionally available newborn inserts, the Sirona Si can even be used from birth (40–60 cm).
Tip: The included Cybex Base S is supplied without the adapter for the Cloud S and is therefore not compatible with the Cloud S, but can be used with the Cybex Anoris S.
360° Rotation for Everyday Family Life
Easy Access and Effortless Buckling Up
Placing your child in the Sirona Si and fastening the harness every day becomes particularly easy. Thanks to the 360° rotation function with one-hand operation, you can effortlessly turn the car seat towards the open car door. This takes the strain off your back and makes placing your child in the seat and taking them out considerably easier. The Easy-In harness buckle provides additional comfort by staying upright on its own. Integrated magnetic harness holders keep the straps secured to the sides, allowing your child to sit down comfortably and making fastening the harness quick and easy.
CYBEX GrowTech: Comfort That Grows with Your Child
Ergonomic Positions for Every Age
Children grow quickly, and the Sirona Si adapts flexibly to their development. The innovative CYBEX GrowTech system combines a height-adjustable headrest with various ergonomic sitting and reclining positions. The ergonomics certified by Aktion Gesunder Rücken (AGR) support a comfortable posture and the healthy M-position of the legs. Compared to its predecessor, the Sirona Si offers a 40% greater adjustment range for reclining positions, both rear-facing and in the more upright forward-facing position. The included comfort insert provides additional support up to a body height of 85 cm. A newborn insert is available as an accessory for newborns measuring 40 to 60 cm.
Enhanced Safety with Side-Impact Protection
Advanced L.S.P. Safety System
The integrated Linear Side-impact Protection system (L.S.P.), together with the energy-absorbing seat shell and headrest, forms a three-stage safety concept. It reduces side-impact forces by up to 25% compared to the same seat without L.S.P. The system can easily be extended at the push of a button during installation. If space inside the vehicle is limited, it can be folded back in to save space.
Optimal Ventilation and Elegant Design
All-Round Ventilation for Comfortable Journeys
The integrated all-round ventilation supports a pleasant seating climate throughout the year. Ventilated hard-shell elements promote air circulation and help keep your child cool and dry. The exclusive Style models also feature innovative 3D mesh fabric that regulates moisture and improves air circulation by up to six times compared to conventional materials. Elegant two-tone leather-look details also give these models a particularly premium appearance.
XXL Sun Canopy with UPF50+
On the Style models, an integrated XXL sun canopy with UPF50+ protects your child from sunlight and reduces distracting light during naps. A breathable mesh window supports ventilation. Thanks to practical clips, you can easily remove the sun canopy and adapt it to different seasons.
All Product Details at a Glance
| Feature | Specification |
|---|---|
| Body Height & Age | 61–105 cm, approx. 3 months to 4.5 years (from birth at 40–60 cm with optional accessories) |
| Maximum Weight | 20 kg |
| Approval Standard | UN R129/04 (i-Size) |
| Weight | 12.4 kg (Comfort) | 12.7 kg (Style) |
| Dimensions (L x W x H) | 560 x 450 x 550 mm |
| Safety Features | Rear-facing travel, L.S.P. side-impact protection, energy-absorbing seat shell |
| Comfort Features | 360° rotation, CYBEX GrowTech, AGR-certified ergonomics, Easy-In harness buckle, magnetic harness holders |
| Ventilation | All-round ventilation, 3D mesh fabric on Style models |
| Sun Canopy | XXL sun canopy with UPF50+ (Style exclusive) |
| Included in Delivery | CYBEX Sirona Si i-Size, base (without adapter for the Cloud S), comfort insert |
| Optional Accessories | Newborn insert, SensorSafe 4-in-1 Kit, summer cover, cup holder |
Kindermaxx Verdict
The Cybex Sirona Si i-Size with Base S combines high safety standards with thoughtfully designed comfort for everyday family life. Particularly impressive features include rear-facing travel up to approximately 4.5 years, practical 360° rotation and the adaptable GrowTech system. The Easy-In harness buckle and magnetic harness holders make everyday buckling up easier, while all-round ventilation ensures a pleasant seating climate. With its AGR-certified ergonomics and already included base, the Sirona Si is an excellent choice for parents who value safety, comfort and ease of use.
| Age: | 3+ months |
|---|---|
| Attachment: | with Isofix |
| Direction of travel: | Backward, Forward |
| Securing with: | 5 - Point Harness |
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