KidShortlist
Diono · High-back booster

Diono Monterey 4DXT

Based on 2 independent scored tests: Insurance Institute for Highway Safety (IIHS), NHTSA (National Highway Traffic Safety Administration) Car Seat Ease of Use Ratings (2021). The test scores average 79. With only 2 tests, the ranking score is pulled down a little until more testers confirm it.

Tested for US & Canada
70
Shortlist score
Good
#108 of car seats for US & Canada
Medium confidence

Where to buy

This seat is certified for US & Canada. Car seats may only be used in the market they're approved for, so we don't link to shops in Czechia.

Test results

Each score as the tester published it, converted to our 0–100 scale. Weight is how much the result counts towards the score.

Insurance Institute for Highway Safety (IIHS) US · Lab test
IIHS booster belt-fit ratings (final ratings list, program 2008-2024) · backless mode
BEST BET
Best Bet
Our scale90
weight 0.40
Tested model #10834-US-01; results also apply to 10880-NA-01, 10886-NA-01; seat type: Dual mode, Backless; rating year not shown on the IIHS ratings list; rating covers booster-mode belt fit only (IIHS does not rate harness modes)
View on iihs.org ↗
NHTSA (National Highway Traffic Safety Administration) Car Seat Ease of Use Ratings US · Government / institute
NHTSA Car Seat Ease of Use Ratings, 2021 · booster mode
3/5★
3 stars
Our scale60
weight 0.24
Labels
3
Instructions
3
Securing child
2
Vehicle installation features
5
NHTSA Ease of Use rating for Booster mode (Highback/No Back); seat type Booster; model #10833-US-01; evaluated seat manufactured 2021-06-01; test_year = year of manufacture of the evaluated seat (NHTSA does not publish a rating date in the data)
View on api.nhtsa.gov ↗
1 older or duplicate result not counted
Insurance Institute for Highway Safety (IIHS) US · Lab test
IIHS booster belt-fit ratings (final ratings list, program 2008-2024) · highback mode
BEST BET
Best Bet
Our scale90
not counted

Not counted: Another configuration scored higher in the same test.

Tested model #10834-US-01; results also apply to 10880-NA-01, 10886-NA-01; seat type: Dual mode, Highback; rating year not shown on the IIHS ratings list; rating covers booster-mode belt fit only (IIHS does not rate harness modes)
View on iihs.org ↗

Top-ranked alternatives

How we turn these into one number: methodology. Tested in 2021.

KidShortlist

We don't test products ourselves. Every score here comes from an independent tester and links back to it. We combine 4,061 results from 26 sources.

Read before buying

Several testers are paywalled, so we only include what they publish openly. Models change and get recalled. Check the tester's own page and the retailer listing before you buy.

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