Stepup i-Size ISOFIX High-Back Booster – Slate Mist, 4-12 Years

A high-back booster with ISOFIX in slate mist grey, for children who have outgrown a harnessed seat — roughly 4 to 12 years.

How a booster works

A booster has no harness of its own. It raises your child so the car's adult seat belt sits correctly — lap belt low across the hips, diagonal across the collarbone.

On an unboosted child an adult belt rides up onto the soft abdomen and across the neck, which is precisely the injury pattern boosters prevent.

Why a high-back rather than a cushion

The back provides side impact protection for head and torso and guides the diagonal belt to the correct height. Backless cushions do neither, and under UK law are only approved above 125cm and 22kg.

ISOFIX or belted?

ISOFIX clips to your car's anchor points so the seat stays put when empty. The belted version at £34.99 relies on the seat belt alone and swaps between cars more easily. ISOFIX for a seat that lives in one car; belted for grandparents or shared vehicles.

Check before you buy

Your car needs ISOFIX anchor points. Check your vehicle handbook and which positions are i-Size approved.

Features

• Approved to UN R129 (i-Size)
• Adjustable headrest
• Side impact protection
• Belt guides for correct routing

Important safety information

Read the manual before fitting. Check belt routing every journey — diagonal across the collarbone never the neck, lap section low across the hips not the stomach.

UK law requires a booster until 135cm or 12 years, whichever comes first. Most children reach 12 before 135cm.

Replace after any collision, however minor. Never use a second-hand seat with unknown history.

Free fitting checks are available at many UK fire stations and retailers.