Britax Kidfix Isize R129 Booster Car Seat - Black
727/0668£199.00
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About this product
Getting them safely to nursery, playdates and family trips becomes simpler. This Britax Kidfix booster seat helps keep children secure from around 4 to 12 years. ISOFIX installation means secure, click-in fitting every time. The integrated SecureGuard adds a 4th point to the 3-point seatbelt. It helps protect little tummies during travel whilst allowing comfortable movement. Air ventilation helps keep them cool on longer journeys.
The adjustable headrest grows with your child, giving years of use. Built-in side impact protection helps shield them during travel. It works with ISOFIX, top tether and the 3-point seatbelt in compatible cars. Suitable for children 100cm to 150cm tall, approximately 4 to 12 years. Supervision required at all times during travel.
Winner of ADAC (1.8), Design Award 2021, German Design Award Winner 2024.
- Car seat group 3.
- Suitable for children from 15kg to 36kg.
- Suitable for children from 100 to 150cm tall.
- Suitable for children approximately 4 years to 12 years of age.
- Seat attachment method: ISOFIX, top tether and 3 point seat belt.
- Integrated ISOFIX.
- Adjustable head support.
- Size H83, W48, D42cm.
- ECE R129 compliant.
- Manufacturer's 2 year guarantee.
- EAN: 4000984312089.
4.8
73 reviews
84%
Recommended this product
Customers Say
The Britax Kidfix i-Size car seat is praised for its safety features, comfort, easy installation, lightweight design, and suitability for children aged 3.5 to 12 years. Minor issues include some build quality concerns and limited recline.
An AI generated summary based on recent customer reviews
Each review is verified as authentic by our independent third party and we only publish reviews from customers or Argos Testers who have purchased or used the item. Customers are incentivised to submit product reviews as part of a prize draw.
Amazing all rounder
My 5 year old fits this seat so well. It is light weight and transfers between cars easily
Dd
Functional and yet stylish
An excellent replacement for my car seat
Seaters, 45 - 54
Car seat
I bought this a month ago on recommendation from my daughter in law who has the same one. Excellent quality and easy to install.
Barnacle, 65 or over, Newcastle
Great safety features.
Bought a few weeks back, really struggled to get a car seat suit kept for my wee one who is 5 has asd. This was most suitable in my budget, he's coping really well the seatbely due to the additional supports across his body and in between his legs. Finds the car seat comfortable. Was really easy to install, love the iso fix and extra safety measures incase of impact. On negative is the writing or print on shoulder pad is starting to come off already.
Hev83, 35 - 44, Scotland
Easy to install
So simple to install and remove if you need the space for an adult. I bought two of these for my grandchildren and they both love them. They are 5 and 6 years old. They both say they are comfortable
Mal, 55 - 64, London
Excellent Car Seat
Easy to fit, brilliant supportive seat. Lap belt clip for extra security is reassuring
FSmith, 35 - 44, West Midlands, UK
Great seat!
Easy to install, seems very safe plus my daughter loves it.
Alex, Cambridge
A lot more plastic with quite rough edges that other seats
we use this in our second vehicle and children seem fairly happy, eldest isn't keen on the chest pad or the crotch strap but tolerating so far, youngest has just moved into this style so happy enough. There is a hard plastic outer shell which will be good in some ways but it comes above the padding so a bit scratchy as still quite rough edges as they slide over them into seat and the two short 'arms' are just plastic with a really rough finish on the joins. If I had looked at them better before the children saw them then I would possibly have sent them back, but we have had Britax before and assumed the quality would be the same especially as this is their 'premium' stage 2/3 seat.
Zara, Cumbria
Good car seat option for older children
We have three KIDFIX i-SIZE seats in different family vehicles and use them every day. For reference our son is 4 years old, a shade over 1m tall and weighs around 20kg. Here's our real world observations starting with the positives: Fitting the seat is pretty straightforward and should take you less than 5 minutes. That said, I got stuck the first time I did it because the instructions supplied by Britax aren't very clear. A quick YouTube search and 30 second video cleared up my problem. My advice is find a video of how to do it and don't bother using the written material supplied with the chair. Once the seat was fitted in the car, I was reassured to find the ISOFIX clamps are sturdy. When fixed into place the chair has very little movement in it. In my experience it can be difficult to release the ISOFIX clamps on some car seats, stiff mechanisms etc. But with the KIDFIX I-SIZE its easy to move the seat if you need to, and the release button is helpfully bright red so you won't miss it. Britax have also clearly marked on the seat where you need to feed the seat belt - as this seat uses the car's seat belt and not its own separate one. Family members who very rarely put our son in the car have said they find it easy and intuitive to use. The seat doesn't weight very much at all and is easy to lift in and out of the vehicle. Being lightweight also makes it easy and convenient to store if you need to remove it from your car regularly. Previously we had a baby and toddlers seat with a separate 360-degree heavy duty base and finding somewhere to store it all when we needed to use the back seat of the car was a chore. With the KIDFIX I-SIZE that isn't a concern. When researching car seats I thought the I-SIZE might be too big, or our child too small, but he fits fine and there's lots of room for him to grow with it. I can't imagine needing another seat after this one. It's easy to move the head rest up and down and can be done when the seat is empty or there's a child in it. We got the seat in black and the design is fine. It compliments the black leather upholstery in our cars and isn't an eyesore. The materials the seat are made from feel OK - neither super premium nor cheap - and the cloth is easy enough to wipe clean. Just recently our son slept for over 90 minutes during a long journey. The seat doesn't have much tilt adjustment in it because the back of the chair has to be snug against the back of the car's back seat for safety. I thought this might mean our son was more inclined to flop forward if sleeping, but this didn't happen once. Our son doesn't sleep a lot in the car anymore so options and configurations that allow him to do so weren't high on our list of priorities, but from our experience, if your little one is tired they'll be comfortable enough to take a nap in the KIDFIX I-SIZE without any issues. The only thing I'm a little disappointed by, and the reason I awarded 4* not 5*, is I've noticed that the cloth cover on the seat comes lose quite often. The cover is designed to stay in place by being tucked into the plastic frame. However, I've found that after regular use, the cover comes away on some of the corners and I have to re-fit it. It's not a big problem and is easy enough to solve, but for a ""premium"" brand, it shouldn't really happen at all. Overall we are really pleased with the KIDFIX I-SIZE. It is a high quality child seat that feels safe, is easy to use and maintain, and is competitively priced. I have no hesitation in recommending it.
Chris, West Yorkshire, UK
Fab
Study, safe and our little boy loves it. Love that it has the xp pad and lap belt support for extra safety, made me feel more comfortable with him being forward facing.
Claire, Belfast
Hello Jade,
The “Britax Kidfix i‑Size R129 Booster Car Seat” is NOT the Pro version.
It is the standard Kidfix i‑Size model.
Thanks for using Q&A
Hello there,
After checking with our supplier, they have advised for the Britax Kidfix Isize R129 Booster Car Seat - Black: The KIDFIX i-SIZE is suitable on the two rear outer seating positions in the Fiat Panda from 2003.
Thank you for using Q&A.
Hello MamaK,
The supplier has advised the following for the Britax Kidfix Isize R129 Booster Seat - Black:
"We can confirm that the KIDFIX i-SIZE is certified i-Size using Isofix and approved Universal using the 3-point seat belt, so will fit most cars. Furthermore, the seat's slim and compact design allows for three seats to be installed in a row in a wide range of cars."
(Without knowing the specific brand, age, and model, we cannot confirm this to be the case for your own car with any certainty though).
Thank you for using Q&A.
Hello There
After contacting our suppliers they have advised for the Britax Kidfix Isize Booster Seat - Black.
The colour may be listed as either Cosmos Black or Space Black depending on the specific car seat model or retailer. However, both refer to a standard plain black fabric, with no significant difference in appearance.
Thank you for using Q&A.
Hello Claire,
After checking with our supplier, they have advised for the
Britax Kidfix Isize Booster Seat - Black: The KIDFIX i-SIZE is approved to use on the two rear outer seating positions in this vehicle.
Thank you for using Q&A.
Hello Staci,
The supplier has advised the following for the Britax Kidfix Isize Booster Seat - Black:
"The KIDFIX i-SIZE does not have a recline feature. However, if the backrest of the car seat is too upright due to the angle of your vehicle seat, you can bring the base of the seat slightly forward to achieve the optimum position."
Thank you for using Q&A.
The small print
*Prices correct as displayed but are subject to change.
The customer and brand answers you’ll see above are submitted independently. As we don’t review these answers, we can’t take responsibility for anything they may say. The responses from Argos colleagues are accurate at the time of publishing. For the latest info, you should check the product page.