Diono Monterey® 4DXT Booster

The original 2-in-1 booster seat with one of a kind, easy-adjust, separate height and width expansion. Transforms from a high-back booster to a backless booster as your big kid grows. With 15 SafePlus® and style upgrades from the Monterey® 2XT. Granted by the Insurance Institute for Highway Safety (IIHS), the BEST BET award is bestowed to car seats and boosters that provide good belt fit for typical ages approximately from 4 to 8 years old in almost any car, minivan, or SUV. The IIHS is an independent, scientific, and educational organization dedicated to reducing injuries and property damage from motor vehicle crashes through the education of consumers, policymakers, and safety professionals.  15 Improvements Re-modeled headrest improves side impact performance Optimized headrest shape improves head containment in the case of a collision Thicker headrest EPP for better child comfort and sleep support Deeper side wings improve side impact performance Built in 3-layer protection sy