The original expandable booster has evolved
Become a VIP Member and earn points & exclusive rewards along your journey. Learn More
Receive perks when you sign up for VIP Rewards

Sign Up
Create a free account and get 100 points.

Earn Points
Every time you shop and share your journey.

Redeem Points
Redeem points for exclusive discounts & perks.

Bonus Points
Exclusive anniversary & birthday bonus.
Monterey® 4DXT
We’ve taken the award-winning Monterey® booster seat and painstakingly engineered 15 upgrades to create the next generation of booster. Suitable from 18 - 54 kg / 40 - 120 lb or approx. 4 – 12 years.
Features:
- 15 UPGRADES FROM MONTEREY® XT - Includes automotive inspired fabrics that cover the entire booster seat back and breathable side panels to enhance airflow to keep your child cool on the move.
- 4 LAYER SIDE IMPACT PROTECTION - Extra deep aluminum reinforced sides provides 4 layers of enhanced side impact protection for their head, shoulders and torso.
- EXPANDABLE HEIGHT & WIDTH - 11 headrest positions and expandable side walls provides 69% increase in occupancy space as your child grows.
- TWO SEATS IN ONE - Easily converts from a high back booster to a backless booster seat with wide contoured seat base and two retractable cup holders.
- QUICK & SECURE INSTALLATION - Equipped with UAS (LATCH) connectors and front adjusters to securely connect the booster seat to your vehicle in seconds, enhancing safety and stability.
Product Specs
- Minimum User Weight: 18 kg / 40 lb
- Maximum User Weight: 54 kg / 120 lb
- Product Height: 69 cm / 27.2 in
- Product Width: 54 cm / 21.3 in
- Product Depth: 41 cm / 16.1 in
- Seat Weight: 8.48 kg / 18.7 lb
- Maximum User Height: 160 cm / 63 in
Care & Maintenance
Warranty Information
Monterey® 4DXT Booster, Instruction Manual, Cup Holder
Diono booster seats can be used for children weighing 40-120 lbs. (18-54 kg) and are 38-63 in. (96.5-160 cm) tall. Typically once a child reaches 5 years of age they are mature enough to ride in a booster seat.
Diono high back boosters with a detachable back are the Monterey® 4DXT, Monterey® 2XT, Cambria® 2. All come with a detachable back to convert into a backless booster seat.
Our booster seats fit 2 across in most cars. Each vehicle model is different and allows for various seating positions. Consumers should consult vehicle owners manual for appropriate car seat placement in their car that may fit more than 2 across.
Solana® comes with fabric cup holders in the cover. Solana® 2, Cambria® 2, Monterey® XT, Monterey® 2XT, and Monterey® 4DXT come with two retractable cup holders. The Monterey® 5iST FixSafe™ includes a Radian® cupholder with easy snap in installation.
The Monterey® 4DXT is recommended to be installed with the lower anchors if you vehicle is equipped with them. However, it can be used without.
Diono booster seats are not meant to be used on airplane. Boosters require a lap/shoulder belt and airplanes only have a lap belt.
All Diono booster seats have a life span of 8 years, starting from the date you purchase your seat. In the event the date of purchase cannot be determined then we use the date of manufacture.
The Diono Difference

Plays well with
Customers Also loved
Rear-Facing Angle Adjuster
Elevates All-in-One convertible car seats to a more upright position