- i-Size and R129 safety – This harness booster meets i-Size and R129 standards. This means Energi i-Size R129 has undergone more extensive side impact testing and is compatible with any i-Size approved vehicle
- ISOFIX and top tether for extra safety – Energi i-Size R129 comes with one-click, colour-coded ISOFIX connectors and top tether installation. In harness booster mode, use both to ensure the car seat stays in place. In highback booster mode, your vehicle’s seat belt is the main installation method, but you may still use the ISOFIX connectors for additional peace of mind
- 2-in-1 car seat – Get more longevity out of this car seat thanks to the 2 forward-facing modes. From 75 to 105cm (15 months to approx. 4 years), use Energi i-Size R129 as a harness booster. When your child reaches 100cm (approx. 3.5 years), you can store the harness away and transition to highback booster mode until your big kid reaches 150cm (approx. 12 years)
- Safety Surround Side Impact Protection – Energi i-Size R129 is equipped with Safety Surround Side Impact Protection, which wraps around your child and provides enhanced head and body protection
- No-rethread harness, 15-position headrest, Built-in ventilation, Integrated colour-coded indicators, Plush memory foam seat, Padded armrests, Integrated harness storage, Open-loop belt guides, 5-point harness, Machine-washable covers
Graco Energi i-Size R129 ISOFIX/Top Tether Harness Booster 76-150cm (15 Months to Approx.. 12 yrs). Harness Mode 76-105cm (15 Months to 4 yrs), Highback Booster Mode 100-150cm…
Sale! (13 customer reviews)

£120.00 Last updated on July 19, 2025 1:08 am
Rated 4.92 out of 5 based on 13 customer ratings
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Graco Energi i-Size R129 ISOFIX/Top Tether Harness Booster 76-150cm (15 Months to Approx.. 12 yrs). Harness Mode 76-105cm (15 Months to 4 yrs), Highback...
£110.00
in stock
Amazon.co.uk
Highest Price
£110.00
Amazon.co.uk
July 15, 2025
Lowest Price
£110.00
Amazon.co.uk
July 15, 2025
Since July 15, 2025
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Model Number | |
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Product Dimensions | |
Item model number | |
Maximum Weight Recommendation | |
Minimum Height Recommendation | 76 Centimetres |
Material Type | |
Material composition | 13.67% (Steel), 18.9% (Polyester, 67.43% (PP,POM,EPP), PE, PP, PU |
Batteries required | No |
Orientation | |
Harness type | |
Item Weight | |
Date First Available |
13 reviews for Graco Energi i-Size R129 ISOFIX/Top Tether Harness Booster 76-150cm (15 Months to Approx.. 12 yrs). Harness Mode 76-105cm (15 Months to 4 yrs), Highback Booster Mode 100-150cm…
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Amazon Customer –
My 3 year old grandson loves it / – it doesn’t block his view out of the window like some other seats. Isofix fitting so very stable.
SHOUTINGman –
prodotto valido e facile da usare
annalisa –
perfetto
Abbas –
I’ve been using the Graco Energi i-Size R129 ISOFIX/Top Tether Harness Booster for a few weeks now, and overall, I’m quite impressed with its performance and versatility. Here’s my detailed experience with the seat:
Installation
The installation process was straightforward. I tested both the ISOFIX and seatbelt options. The ISOFIX system, in particular, was very user-friendly. The prongs pop out with the push of a button, and it comes with handy guides that make the installation process smoother, especially if your vehicle has deep-set anchors. While I didn’t personally need these guides, I can see how they would be useful for many.
Comfort and Fit
I’ve used this seat with both a smaller child in harness mode and an older child as a highback booster. Transitioning between the two modes was seamless. The seat’s adjustability is fantastic, particularly the headrest, which moves up and down easily to accommodate your child’s growth. The armrests add a nice touch of comfort as well.
Cleaning and Maintenance
An unexpected benefit of this seat was how easy it was to clean after my child had an accident. Removing the cover was intuitive, involving a simple process of unclipping or untucking around the crevices. I washed it according to the instructions on a 30-degree wash, and it came out perfectly clean without any signs of wear or tear. Reassembling the cover was slightly more challenging than removing it but still manageable and it fitted back perfectly, looking as good as new.
Safety and Features
Safety is paramount, and the Graco Energi does not disappoint. The top tether adds an extra layer of security, ensuring the seat is firmly in place. The harness mode felt incredibly secure for my smaller child, and the highback booster mode provided ample support for the older one. The seat’s design blends well with the car’s interior, making it a visually pleasing addition.
Build Quality
The overall build quality is impressive. The materials used feel durable and premium, and the seat itself is sturdy yet comfortable. My child found it so comfortable that he felt like he had a new toy to play with, which speaks volumes about its child-friendly design.
Final Thoughts
This seat is highly versatile, catering to children from 15 months up to approximately 12 years, making it a worthwhile investment. It arrives in a compact, tall box and requires some assembly, but the process is easy and quick.
In summary, the Graco Energi i-Size R129 ISOFIX/Top Tether Harness Booster is an excellent car seat that combines safety, comfort, and ease of use. It’s a highly recommended choice for any parent looking for a reliable and adaptable car seat for their growing child.
Vittorio –
Il prodotto è molto comodo e spazioso, facile da montare grazie all’isofix.
louise –
Ottimo acquisto, la nipotina rimane comoda, è spaziosa robusta e facile da bloccare
Abbas –
It fitted in my car well. It is of excellent quality. Its installation is very easy, taken me few minutes to install.
The cover of the seat itself is spill proof and is fitted firmly on the seat. Although quite difficult to remove for washing, still can be washed if get dirtier.
Overall, I would recommend and trust 100% for my child’s safety.
SHOUTINGman –
Bon siège auto, avec la norme européenne de sécurité R129….. Installation un peu difficile, pas de notice, dans l’emballage, mais possibilité de télécharger sur internet…Après visionnage de la notice installation plutôt facile et rapide… Confortable, notre petit fils s’y est endormi 😴🙂…Un prix abordable pour un bon siège auto…Merci , je recommande ce produit…
T I T A N –
This seat is a very high quality one. I have had Gracco in the past and they last forever.
This one is an ISO Fix which makes it really easy to use. Open the flaps in your cars seat and press home to lock into place. Removal is also easy as there are release buttons on each side of the seat.
The seat itself has harnesses for you smaller children but will grow with your child initially with the harness then the headrest lifts and then with the full seat and seatbelt from the car and finally with the back removed again using the seat belt of the vehicle.
The covers are removable for washing but it is pretty tricky, thankfully the material is high quality and wipeable to begin with.
Really good car seat to trust with your precious one.
LRT –
Great quality car seat. Lots of room for my 3yr old and should last him for years to come.
Muzammel –
Really like this i-size car seat. It’s not too big or bulky, it’s easily transferable between cars and grows with your child. One of the big reasons i bought this over some others is that it is secured with an isofix and top tether so gives me that extra piece of mind
Alaa Baa –
Not soft, short belts
Amazon Customer –
My 2.5 year old had reached the height limit of his rotate car seat and the headrest wouldn’t go up any further with the harness in use but he was definitely not ready for a seatbelt. This seat is great. Easy to install, feels secure, child looks comfortable and can still nap in it. The headrest goes up high enough when using the harness to accommodate his long back! Would definitely recommend.