It fits perfectly over the Britax Marathon car seat. The fabric is not only precious, but great quality, and I love the inner waterproof lining. I didn't really care for any of the car seat covers made for girls by Britax, but I LOVE their car seat, so the Bumble Bags cover works perfectly for us! Now we not only have a great, safe seat, but one that is CUTE too! If in doubt if this cover will fit your seat, just call the manufacturer before purchasing.

This keeps my daughter so comfortable in her toddler carseat, I LOVE the print-- the picture does not do this cover justice-- it is a beautiful pattern of a subtle pink with feminine blossoms and brown accents. It has saved the condition of our carseat-- even with the "abuse" from my daughter's juice boxes, crackers, even yogurt, etc, we just pop it in the wash, let it air-dry, and put it back on-- the carseat is like new-- smells and feels great! It has a light padding (goes over my existing carseat padding), and the feel of the fabric is so light and soft. I would have never imagined it would be this durable and sweet at the same time. Hollywood mommies carry Bumble products, which is never the basis of my purchases, but Heaven knows they can afford anything, and this is what a lot of them choose, from what I've seen in US Weekly anyway. Yes, I can be "that" mom at times ;) LOL!
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br /I have no idea why this would be called a "bad idea" and if you were trying to collect on a carseat warranty, why would you even say "I have a carseat cover" on the carseat? It's not like the cover will damage the seat (it only protects it), so why bring it up to the warranty department in the first place? I don't get it, though I respect all opinions. Also, given that is not a "strickly tailored" fit, I would think that it works with just about any carseat. I've used mine on three different carseat models and they have all worked out fine.
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br /Cute, comfy, and love it!

You should only use car seat covers that are made or approved the the manufacturer! After-market products may void your warranty and release the car seat manufacturer of any liability.