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CybexSirona Ti i-Size Plus

i-Size baby to toddler
Isofix connectors and support leg
Extended rear-facing seat

£329.95View retailers

Test score

Lowest available prices

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Cybex claims that its Sirona Ti car seat will be the perfect fit from baby to toddler, with a reclining seat and an extra cushion for newborns. Can it also offer the safety parents expect on car journeys? Read our review of this car seat to find out.

pros

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cons

What's included?

What is it?
How safe is it?
Is it easy to fit?
Is the seat comfortable?
Is there anything else I should know?
Should I buy it?
Where can I buy it?

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KEY TEST RESULTS
Safety rating
Fitting in car
Comfort of your child

May 2026First reviewed by Which?
Dec 2025Released

The overall Which? test score is made up of the following star ratings, all determined by our rigorous lab tests.

Two child safety seats in the back of an orange van, each holding a crash test dummy with green heads.

How we test baby and child car seats

22 Oct 2025

Safety rating

How we test safety rating

The overall safety score is made up of the results of crash testing (front crash; side crash) seat design, stability in the car and belt routing. Our crash tests go beyond the legal minimum requirements for UK car seat regulations and are conducted at higher speeds and forces than the regulations require. We feel our tests more accurately reflect what could happen in a real life crash.

Fitting in car

Overall
Buckling up
Avoiding misuse and instructions
Cleaning
Space required in car

How we test fitting in car

Fitting and using includes: How easy it is to install the seat correctly in the car. How easy it is to strap a child securely into the seat. How well the seat is designed in order to prevent incorrect use. How easy the seat cover is to remove and wash. How little space the seat takes up in the car and how comfortable your child is in the seat.

Ergonomics

Overall
Comfort of your child

How we test ergonomics

Our experts conduct an ergonomic assessment of each seat to make sure your child will be in the best position when travelling, along with the level of padding and support. Our tests also reveal how much space this car seat takes up in the back seat of a car and how easy it is to get your child in and out of the seat. Plus, our eagle-eyed car seat experts will check whether this seat affects how much space any front passengers have. This assessment was introduced to our site in May 2015. If a seat does not have this score, it was tested before May 2015.

General
Height of child	40cm-105cm
Seat size	i-Size baby to toddler
Age group	Baby to toddler
Direction of travel	Reversible
Extended rear-facing seat	Yes
Installation type	Isofix connectors and support leg
Harness or shield seat	Harness
How is the child held in the seat?	5 point harness

Features
Isofix integrated into seat	Yes
Isofix base	Yes
Belted base	No
Type of Isofix	Isofix connectors
Swivel seat	Yes
Weight of seat (kg)	13.5kg
Part of a travel system?	No
Harness height adjustment	Moves with headrest
Recline	Yes
Adjustable headrest	Yes

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Prices are ordered from lowest to highest, irrespective of retailer rating or stock, and exclude any potential delivery costs. We are not able to show every possible retailer and cheaper prices may be available.

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CybexSirona Ti i-Size Plus

Lowest available prices

Sign up to unlock the full expert review

pros

cons

What's included?

How we test baby and child car seats

Safety rating

Fitting in car

Ergonomics

Compare retailers

How this product's score compares with other child car seats we've tested

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CybexSirona Ti i-Size Plus

Lowest available prices

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cons

What's included?

Test results

Specifications

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Best Buys & Don't Buys

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