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Britax RömerHi-Liner

i-Size child
Vehicle seat belt and isofix connectors

£119View retailers

Test score

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The Britax Romer Hi-Liner is a high-backed booster car seat approved to R129 i-Size regulations. It’s got an adjustable back rest and headrest, and Britax claims that it’s slim enough that you can fit three across the back row of seats in a range of vehicles. Read our review of this car seat to find out if it’s safe, easy to install and comfortable.

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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?

Full Access first month £5, then £11.99 per month, cancel at any time

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

May 2024First reviewed by Which?
Apr 2023Released

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

How we test baby and child car seats

16 Apr 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	100cm-150cm
Seat size	i-Size child
Age group	Child
Direction of travel	Forward facing
Extended rear-facing seat	No
Installation type	Vehicle seat belt and isofix connectors
Harness or shield seat	Adult 3 point seat belt
How is the child held in the seat?	Vehicle seat belt
Manufacturer URL	https://www.britax-romer.co.uk/

Features
Adult seat belt	Yes
Isofix integrated into seat	Yes
Isofix base	No
Belted base	No
Type of Isofix	Isofix connectors
Swivel seat	No
Weight of seat (kg)	6.1kg
Part of a travel system?	No
Harness height adjustment	Moves with headrest
Adjustable headrest	No

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Britax RömerHi-Liner

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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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Britax RömerHi-Liner

Lowest available prices

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Test results

Specifications

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