This all-in-one seat is in it for the long haul, packed with pluses like side impact protection, adjustable headrest, expanding shoulder width, and harness storage. It goes from cradling your napping newborn to supporting your independent tween. For big & small, for short & tall. TRES seamlessly follows the transition of your child from toddler to big kid. This all-in-one seat is in it for the long haul, packed with pluses like side impact protection, adjustable headrest, expanding shoulder width, and harness storage. It goes from cradling your napping newborn to supporting your independent tween.