What are the weight and height recommendations for using this car seat?

The child must weigh between 30 and 100 lbs (13.5 kg to 45.5 kg) with harness in toddler mode, and between 40 and 100 lbs (18 kg to 45 kg) for high-back booster mode without the built-in harness system. For backless booster mode, the requirements are weight of 40-100 lbs and height of 42-57 inches (107-145 cm), with other additional conditions (Page 16).