SKU: 66151563804
britax seat extender

britax seat extender Britax Grow With You Harness 2 Booster Seat - Jillians Drawers

$21.21 $23.57
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Ships within 48 hours · Estimated delivery Aug 2 - Aug 7

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Description

britax seat extender Britax Grow With You Harness 2 Booster Seat - Jillians DrawersAllow for 2 week shipping time. The Grow With You Harness Booster Seat is a harness 2 booster seat that grows with your child from toddler to big kid. With the patented ClickTight Installation, youll know its right in 3 easy steps. 2 layers of side impact protection surround the head, neck & torso. Plus, SafeCell Impact Technology creates a crumple zone that absorbs crash energy. Features we love: The ClickTight installation system gives you the

Allow for 2 week shipping time. The Grow With You Harness Booster Seat is a harness-2-booster seat that grows with your child from toddler to big kid. With the patented ClickTight Installation, you’ll know it’s right in 3 easy steps. 2 layers of side impact protection surround the head, neck & torso. Plus, SafeCell Impact Technology creates a crumple zone that absorbs crash energy.

Features we love:

The ClickTight installation system gives you the safest and easiest installation every time so you are certain your little one is protected.
Offers the best protection for your child with two layers of side impact with its energy-absorbing shell and foam-lined headrest to protect your child’s head, neck, and torso.
9-Position, Quick-Adjust Harness & Headrest that move together to create the proper fit as your child grows.
2 Recline Positions help you find a comfortable fit for your child and the best fit for your vehicle.
4-way stretch athleisure fabric combines style and function for a modern look that’s easy to keep clean.
Install confidently, every time. With ClickTight, you know it’s right in just 3 easy steps. Open, thread & buckle, close.
SafeCells in the car seat base create a crumple zone that absorbs crash energy to help keep it away from your child.
Industrial Strength Steel frame reinforces the seat structure to help keep it stabilized.
V-shaped tether with staged-release stitches helps slow and reduce forward movement during a crash.
Energy-absorbing chest pads reduce your child’s forward movement during a collision.
2 Layers of Side Impact Protection: Energy-absorbing shell and foam-lined headrest protect your child’s head, neck, and torso.
2-position buckle can be moved outward to accommodate your growing child.
Color-coded belt guides make it easy for you and your child to route the seat belt through the right paths.
Easy-to-remove cover for cleaning without uninstalling the car seat or removing the harness.
Stay-put, soft comfort pads keep your child’s neck from rubbing against the harness strap.
Flip-forward buckle stays out of the way for easy boarding.
Easy-to-clean arm rests 

Product Size

  • Product Dimensions: 21" L x 19" W x 25" H
  • Car Seat Weight: 23 lbs
  • Child Weight Capacity:
    • Harness mode 25–65 lbs
    • Booster mode 40–120 lbs
  • Child Height Capacity: Up to 63"
Child Weight - Forward Facing Harness 2 years old & 25 - 65 lbs  
Child Weight - Booster 40 - 120 lbs  
Child Standing Height - Forward Facing Harness 30 - 49"  
Child Standing Height - Booster 45 - 63"  
Child Seated Shoulder Height - Forward Facing Harness 12.5 - 20.5"  
Child Seated Shoulder Height - Booster 15 - 23"  
Product Weight 23 lbs  
Product Dimensions - Harness Minimum 19" W x 28" H x 21" D  
Product Dimensions - Harness Maximum 19" W x 36" H x 21" D  
Product Dimensions - Booster Minimum 19" W x 28" H x 21" D  
Product Dimensions - Booster Maximum 19" W x 36" H x 21" D  
Seat Compartment Height 23.5"  
Seat Area Depth / Width 13.5" / 12"  
Shoulder Width 15.5"  
Harness Slot Heights 12.5" / 13.5" / 14.5" / 15.5" / 16.5" / 17.5" / 18.5" / 19.5" / 20.5"  
Buckle Strap Depths 7.0" / 9.0"  
*Recommendation Britax strongly recommends that children should be secured with a harness system until they exceed the weight or height limits specified.

Care

Read how to care for your car seat here

Warranty

Limited 1 year warranty information can be found here.  9 year expiration.

Video


Product Origin: Proudly designed, tested and built in the USA with US and global components for safety and quality.

About Britax
At Britax, we believe family life should be lived without limit. A world where parents and children are free to make the most of every moment together. And we think it's our responsibility to make this happen. By driving safety standards to ensure children have never been better protected on the move. By pushing boundaries in smart design to make life in motion run smoothly. By extending a helping hand – or two – and always celebrating the journey.

We've been leading the way in child safety technology for more than 70 years. Always innovating, always focusing on what's best for the child, always going beyond 'good enough'. From Europe's best-selling car seat brand, we've become one of the brands most trusted by American families since we launched here in 1996.

Since then, we've revolutionized side impact protection, transformed safe seat installation, and introduced a range of smart strollers designed around the changing needs of today's families.

Our ongoing, open-ended conversation with parents is complemented by our work with car manufacturers, government bodies, and child passenger safety experts – collaborating, advising and using our industry-leading testing facilities to continually find ways to give parents the products and the reassurance to live family life without limit.

Because we believe in helping every parent and every child find their family freedom.

Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 66151563804

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4.1 ★★★★★
Based on 23 reviews
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Product Reviews
D
Verified Purchase
David Spencer
Lake Worth, US
★★★★★ 5
Good stuff
Material Type: 157mil Closed Cell Foam, Style: 157 mil 36 SqFt
Good stuff, easy to use, self adhesive backing contours around curves easily and works great.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 29, 2026
S
Verified Purchase
stookie778
Omaha, US
★★★★★ 5
Works amazingly, but only if you install it correctly.
Material Type: 157mil Closed Cell Foam, Style: 157 mil 36 SqFt
If you purchasing Siless Liner 157 mil (4 mm) Sound Deadening mat, to block unwanted sounds in your car, this is what you need to buy. But wait! It's not the only thing you need to buy if you want to "actually" deaden sound. By itself, it will definitely block a noticeable amount of sound, and, most likely, that's all you realistically need. But... But... If you want the Siless Liner Sound Deadening Mat to really help you take it up a few notches, to get the best sound almost bordering on soundproofing, listen up. You will have to install traditional butyl rubber first. Doesn't have to be the Siless brand, but I'm sure they would love to sell both to you, I used both Killmat (80mil) and Noico (50mil). I have a Honda S2000. It's a two-seater convertible sports car if you don't know what this car is, and it's loud when I'm driving above 60mph. I also happen to have a sound system installed as well. Other than that, the car is stock. I first installed the butyl rubber on the car's interior sheet metal. I went all out and covered everything I could. I didn't need to but I wanted to. I was extremely impressed with the results. But I wanted to go further. Not because I needed to but because just wanted to see what it would be like. So I bought Siless Liner 157 mil (4 mm) 36sqft Sound Deadening mat to go on top of the butyl rubber mats. I put this over every area I installed the butyl rubber. I had to be careful of clearance issues since I added a significant amount of underlayment, and you should too. If you put butyl rubber sound-deadening materials in 50% of the total interior area, you'll hear a noticeable improvement. If you put butyl in about 80% of the total area, you'll be even more amazed at the improvement, compared to before. I originally did all the above myself, so that's my experience and so your mileage may vary. I then installed the Siless Liner Sound Deadening mat over every place I could even going further than I could with the butyl rubber. I used the Siles Liner in areas where butyl rubber would not have been effective, such as the roll bar hoop area and large empty cavities or holes. I covered everything I could, firewall, doors, floor pan, transmission tunnel, trunk, trunk lid, fuel tank area, rear quarter panels, and rear-wheel tunnels, in Siless Liner Sound Deadening Mat. WOW!! The Siless Liner Sound Deadening Mat was the icing on the cake! Let's not forget, this car is a convertible sports car so it will never be a quiet ride, ever. But I can now actually have a conversation with a passenger at a normal-ish volume! This also means I can now have a normal hands-free phone call without having to plug one ear to block out the noise! My sound system sounds so much better! Just by going through the install process, I looked for any vibration, rattle, squeak, and noise-prone areas to either eliminate or reduce unwanted noise production. If you forget this step, the inside and outside of your car will rattle and buzz. I skipped this step the first time around. But did it right before I installed more butyl rubber and the improvement was impressive, especially inside the car. Outside the car, I didn't notice a difference until I put the last layer of Siless Liner Sound Deadening Mat. The sound deadening mat works both ways from what I can tell. If I turned up my music, as loud as I occasionally do, parked in the attached garage to the house, with the garage door closed, I would be barely able to tell the car was playing music in the garage. It sounds like it is another car, just a little bit down the street, with a very loud base. If you stand 20 feet away outside the car, the sound system is noticeable, but not obnoxious by a long shot. Get a 3 piece wood/metal roller set as well, which makes quick work of large areas.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on December 23, 2021
L
Verified Purchase
Ligia
Carnegie, US
★★★★★ 5
Better than Kilmat
Material Type: 157mil Closed Cell Foam, Style: 157 mil 36 SqFt
Great adhesion, and you can immediately see the sound difference when you rap the area and compared it to another area without it. Also, very easy to cut and apply. Once on, you may not be able to peel it and reposition it, so be sure where you want it.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on March 2, 2026
J
Verified Purchase
J M.
Whiting, US
★★★★★ 3
Not much noise reduction…
Material Type: 157mil Closed Cell Foam, Style: 157 mil 36 SqFt
Easy to install but did not provide much sound dampening…
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 28, 2026
M
Verified Purchase
Mike
Carnegie, US
★★★★★ 5
Great sound mat for the price!
Style: 50 mil 50 SqFt, Style: 50 mil 50 SqFt
This is a good product. Many people go with KILMAT because of the value to price point. I did as well. When you clean the surface (in my case it was all painted metal) this stuff sticks very well. I do recommend you use a seam roller of some type, I used Lumiteco 3 piece roller set. This will help with adhesion and mostly flatten the overlapped edges. It also helps you see where you have rolled as it leaves little grooves. The difference when we had no sound mats and after was very impressive. We haven't finished our install yet and it is quieter than when we had an interior in the van. There are thicker mats available in other brands, but this will work great for our van build, but this helps keep the weight down. It is quality material, just be careful when you are removing the backing, the edge of the foil face can cut you. I suggest you layout where you are installing the mat and cut to fit. From what I have read, you don't need to cover every inch in the vehicle, just spot install for a big difference. I chose to cover most surfaces to help keep sound out when we are sleeping in the van. We haven't finished putting the van yet, but we have driven it around and been very satisfied with this product.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on December 3, 2025

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