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Diono Radian 3QXT Convertible Car Seat

Diono Radian 3QXT Convertible Car Seat

Regular price $449.99
Regular price Sale price $449.99
Sale Sold out
Color : Gray Slate
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The Diono Radian 3QXT Convertible Car Seat is the ultimate 3-across, all-in-one car seat. It transitions from infant car seat to booster seat and features advanced 4-in-1 newborn protection and all new Safe+ engineering to provide the next generation in car seat safety.

You'll love that is can grow with your child for ten years--from 4 to 120 lbs--and your child will love how comfortable it is, with tons of features to ensure maximum comfort, including a contoured,12-position headrest and Comfort+ memory foam cushioning.


    •  Adapts for 10 years of use, from infant to booster seat, rear and forward facing, 
    • Slim fit design for 3-across seating
    • 4-in-1 newborn protection with Safe+ inserts
    • Safe+ steel anti-rebound bar to reduce rebound rotation by 50%
    • Steel-reinforced frame
    • 8 layers of side-impact protection with side-impact management pod
    • Diono SuperLATCH attachment
    • One-hand, easy-adjust 12-position headrest 
    • Comfort+ memory foam cushion
    • Machine washable cover

    Installation Options

    • Rigid LATCH
    • Seatbelt Installation 

    What's Included

    • Diono Radian 3QXT Convertible Car Seat
    • Rear-Facing Base
    • 4-Stage Newborn Inserts: Protection Insert, Travel High Wedge, 2-in-1 Infant Positioning Liner, Harness Pads
    • Cup Holder
    • SafePlus™ Steel Anti-Rebound Bar & Side Impact Management Pod
    • Harness Pads and Lap Belt Cushion


    Weight/Height Capacity 

    • Weight: 4-120 lbs
    • Rear Facing: 4-50 lbs
    • Rear Facing LATCH Maximum User Weight: 35 lbs
    • Forward Facing: 22-65 lbs
    • Forward Facing LATCH Maximum User Weight: 40 lbs
    • Booster: 40-120 lbs
    • Maximum User Height: 57.1"

    Weight and Dimensions 

    • Weight: 32 lbs
    • Dimensions: 28.5"H x 17"W x 16"D 
    • Folded Dimensions: 28.5"H x 17"W x 11.5"D

    Materials and Care Instructions

    Covers: Machine wash cold, line dry. Shell and Components: Spot clean

    Compatibility + Accessories


    • Radian Car Seat Travel Backpack
    • Ultra Mat and Heat Sun Shield Car Seat Protector
    • Radian Rear-Facing Angle Adjuster
    • Radian XL Cup Holder - 2 Pack

    CPS Techs

    What is a CPS tech?

    A CPS tech is a Certified Passenger Safety Technician. Our Cubby Moms who have certified as CPS techs are specially trained on how to properly install car seats and booster seats, ensuring they know everything there is to know about keeping children safe in vehicles.
    Through required continuing education courses and hours of personal research and team training, our CPS techs are able to remain up to date on the latest technical information regarding child safety.
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    How does a CPS tech get certified?

    In order to become certified, each prospective tech must attend The National Child Passenger Safety Certification Training Program. After intensive classroom instruction, they must pass a variety of written tests, demonstrate their knowledge through hands-on skills assessments, and perform safety checks at a check-up event before becoming certified. They learn the ins and outs of car seat installation possibilities, installing car seats in different vehicles, harnessing methods, and more. The car seat and safety industry is constantly changing, so our CPS techs here at The Baby Cubby are an invaluable resource for parents purchasing a new car seat, or for ones who simply want someone to double check that their current car seat is properly installed.
    Customer service icon

    How can I get in contact with a CPS tech?

    You can visit our store during regular business hours to consult with a CPS tech. This is a service we provide all year round because we’re passionate about helping parents and keeping kids safe! If you’re not local, you are always welcome to contact The Baby Cubby via phone to get the peace of mind our highly-trained techs can offer when it comes to child car safety. To contact our CPS techs, use the options listed below.





    Car Seat Return and Shipping Policy

    Car Seat Returns

    Due to safety concerns, only unopened car seats can be returned. Safety is our top priority and we want you to keep your kiddos safe. If you have any questions, please reach out to 

    Car Seat Shipping

    Free Shipping applies to standard shipping orders over $95 within the continental U.S.A. Unfortunately, orders shipping to Alaska, Hawaii, Puerto Rico, or APO/FPO addresses do not qualify for free shipping.
    Large furniture items that must ship as freight such as cribs, gliders and dressers have a separate furniture delivery fee.

    Free 5-7 days shipping is available on every order over $95 (excluding taxes and shipping fees) in the continental U.S.A. If you are in need of expedited shipping, the cost will be dependent upon your area and how fast you are wanting it shipped to you. You can get a shipping quote in your cart at checkout.

    Shipping Timeline

    For standard shipping, FedEx and USPS have up to 5-7 business days to deliver your order. However, most items arrive within 3-5 business days.

    To track your package, follow one of the links below:

    United States Postal Service (USPS) Tracking:

    FedEx Tracking:









    Best Price Guarantee


    We understand that caring for a baby isn’t cheap
    and that baby gear and supplies quickly add up. If
    you find a lower price on any item that we sell, we
    will gladly match it.

    The product must be the exact same color/style/size
    and be in stock on competitor’s website. Unfortunately,
    we cannot price match auction-based websites. Some
    brands and manufacturers are excluded from our price
    match policy. Some items have a 1 per person price
    match as well.


    To obtain a price adjustment, please contact email
    Customer Service at


    A one-time price adjustment per item will be honored
    when items are purchased at full retail price and the
    merchandise (of the same style, color, and size) is
    discounted within 14 days of the original purchase date.
    Price Match Exceptions:
    Items purchased with a promo code or discount code are
    not eligible for price adjustments.
    Price adjustments are not provided during Black Friday or
    Cyber Monday sales.
    The following brands are not eligible for price adjustments:
    Creative Co-op and Jamie Kay
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