Diono Monterey 6DXT SafePlus High-Back Booster
The Diono Monterey 6DXT SafePlus High-Back Booster is 17.7 in wide, weighs 16.3 lb, and has a booster weight limit of 120 lb, per Diono. High-back belt-positioning booster from Diono with LATCH connectors; the backless mode requires a vehicle headrest.
- $209.99List price
- 120 lbBooster to
- 16.3 lbSeat weight
- 17.7 inWidth
Monterey 6DXT SafePlus High-Back Booster: key facts
- The Diono Monterey 6DXT SafePlus High-Back Booster works as a booster from 40 to 120 lb and 38 to 63 in tall, per Diono.
- Outgrown by height: "DO NOT use this child restraint backless unless there is a vehicle headrest for that seating position."
- It installs with LATCH.
- Diono says it expires 8 years after the date of manufacture.
- Diono says it isn't certified for aircraft.
- It's 17.7 in wide at the widest point and weighs 16.3 lb.
From Diono's manual and published specs. Always follow the limits on your seat's labels.
How the Monterey 6DXT SafePlus High-Back Booster stacks up
Against the 65 booster seats we track. The shaded band is where the middle half of them fall; the dot is this one.
Within the typical range for booster seats (100 lb to 120 lb).
Within the typical range for booster seats (8 years to 10 years).
Within the typical range for booster seats (17 in to 18.6 in).
Above the typical range for booster seats (6 lb to 13.2 lb).
Above the typical range for booster seats ($55.99 to $159.99).
What sets the Monterey 6DXT SafePlus High-Back Booster apart
Measured against the 65 booster seats we compare, from each maker's published specs.
- Width: 17.7 inin the middle half of the 31 booster seats that publish it (17 in to 18.6 in)
- Weight: 16.3 lbabove the middle half of the 42 booster seats that publish it (6 lb to 13.2 lb)
Next to its closest matches
- Maxi-Cosi RodiSport 2-in-1 Belt-Positioning BoosterNext to it, the Monterey 6DXT SafePlus High-Back Booster is 20 lb higher booster limit; 2 years shorter before it expires; 0.5 lb lighter.
- Britax HighpointNext to it, the Monterey 6DXT SafePlus High-Back Booster is 2 years shorter before it expires.
- UPPAbaby Alta V2Next to it, the Monterey 6DXT SafePlus High-Back Booster is 20 lb higher booster limit; 0.2 in wider; 0.7 lb lighter.
Flying with the Monterey 6DXT SafePlus High-Back Booster
Diono's label: “Diono® booster seats cannot be used on airplane.” American lists “Booster seats with no approval label or shoulder harness” under seats and devices not approved for use on board (source).
What airlines say about car seats:
- American: “Each ticketed customer is allowed 1 stroller and 1 car seat to be checked free of charge” “If an unoccupied, adjoining seat is not available, the gate agent will check the safety seat to your final destination.” Source
- Alaska: “We will transport your child's car seat and stroller free of charge as checked baggage.” Source
- JetBlue: “Checking a child safety seat will not count towards your checked baggage allowance and there is no fee assessed” Source
- Spirit: “One (1) car seat will be accepted per child as checked baggage at no charge.” Source
- Frontier: “strollers and car seats can be checked for free.” Source
- Allegiant: “There is no charge for checking or gate checking one car seat per fare-paying passenger.” Source
- Breeze: “Child seats may be carried on board the aircraft if a seat has been purchased for the Infant or Child” Source
Quoted from each airline's page as of 2026-11-02.
Listed features
- Lists a 40-120 lb range
- LATCH connectors for attaching the booster
- Backless use is allowed with a vehicle headrest
Worth checking
- Maker states it cannot be used on an airplane
- Maker's age guidance is only 'typically five years'
- 8-year life span counted from purchase date
Where to buy the Monterey 6DXT SafePlus High-Back Booster
Prices and availability change. We may earn a commission from some links.
- Check for recalls: Search the agency's recall list with the model number and date code from the label: NHTSA recall search.
- Car seat use and installation: see NHTSA's car seat page, which also lists free car seat inspection by certified technicians. Check the label and the maker's instructions, and ask your pediatrician about your child.
Full specs
| Diono Monterey 6DXT SafePlus High-Back Booster | |
|---|---|
| Type | Booster |
| List price | $209.99 |
| Booster weight | 40–120 lb |
| Booster height | 38–63 in |
| Seat weight | 16.3 lb |
| Width | 17.7 in |
| Head rule | DO NOT use this child restraint backless unless there is a vehicle headrest for that seating position. |
| Installation | LATCH |
| Load leg | No |
| Anti-rebound bar | No |
| Rotates | No |
| Aircraft label | Not certified for aircraft |
| Expires after | 8 years |
Compare the Monterey 6DXT SafePlus High-Back Booster with
How each closest rival differs from the Monterey 6DXT SafePlus High-Back Booster, from the makers' specs.
- Maxi-CosiRodiSport 2-in-1 Belt-Positioning Booster16.8 lb$199$199.99
- 20 lb lower booster limit
- 2 years longer before it expires
- 0.5 lb heavier
- BritaxHighpoint$219booster to 120 lb$219.99
- 2 years longer before it expires
- $10 more
- UPPAbabyAlta V217.5 in wide17 lb$199.99
- 20 lb lower booster limit
- 0.2 in narrower
- 0.7 lb heavier
- Maxi-CosiTanza High-Back Belt-Positioning Folding Travel Booster16.5 lb$229$229.99
- 20 lb lower booster limit
- 2 years longer before it expires
- 0.2 lb heavier
Monterey 6DXT SafePlus High-Back Booster: questions answered
From Diono's published specs, last checked 2026-11-06.
Will the Diono Monterey 6DXT SafePlus High-Back Booster fit three across or in a small car?
It's wider than 56% of the boosters we track, at 17.7 in. The narrowest is the Mifold Comfort Grab-and-Go Booster at 10.2 in. Fit depends on your vehicle; check each seat's manual and your vehicle manual. Car seat use and installation: see NHTSA's car seat page, which also lists free car seat inspection by certified technicians. Check the label and the maker's instructions, and ask your pediatrician about your child.
Can you bring the Diono Monterey 6DXT SafePlus High-Back Booster on a plane?
Diono doesn't list it as certified for aircraft, so it can be checked as luggage but not used in the plane seat. See seats approved for planes.
Monterey 6DXT SafePlus High-Back Booster or RodiSport 2-in-1 Belt-Positioning Booster: what's different?
By the makers' specs, the RodiSport 2-in-1 Belt-Positioning Booster lists for $10 less. See every spec side by side.
Is it OK to buy a used Monterey 6DXT SafePlus High-Back Booster?
NHTSA publishes guidance on used car seats on its car seat page. Diono lists a lifespan of 8 years from manufacture for this model. Check the label and the maker's instructions, and ask your pediatrician about your child.
Still wondering? Write to us at hello@cribpicks.com and we'll look it up.
More booster seats
- ChiccoKidFit Zip Air Plus 2-in-117 in wide11 lb$186.99
- MifoldHifold15.6 in wide10 lb$249.99
- DionoMonterey 5iST FixSafe17 in wide18.7 lb$259.99
- ChiccoKidFit Zip Plus 2-in-117 in wide10 lb$159.99
- ClekOlli18 in wide5 lb$149.99
- ChiccoKidFit Adapt Plus 2-in-117 in wide10 lb$149.99
Where these specs come from
- store.diono.com/monterey-6dxt-safeplus-high-back-booster
- diono.zendesk.com/hc/en-us/article_attachments/35338805546899
- target.com/p/-/A-93189990
Last checked 2026-11-06. Spot something wrong? Tell us. Read our editorial and safety policy and corrections.