What are the weight and height limits for rear-facing use?

The rear-facing weight limit is 2.3 to 18 kg (5 to 40 lbs) and the height limit is 48 to 102 cm (19 to 40 in.). Additionally, the top of the child's head must be at least 25 mm (1 in.) below the top of the child restraint seat back. Once your child exceeds any of these requirements, they must transition to forward-facing use if possible, or discontinue use if they are under 2 years old. (Page 2)