KneeGuardKids are not the products to stand on or use as a step to get into the car seat.
Be sure to use it for its intended use to sit on the car seat and then raise your feet.
Therefore, if you only use it for the original purpose, you can use it regardless of age while using the car seat.
However, we recommend the following age and weight for safe use.
KneeGuardKids2: Available for children under 6 years. (Weight less than 20kg)
KneeGuardKids3: Available for children under 9 years. (Weight less than 30kg)
For reference, KneeGuardKids3 can withstand loads up to 192 kg under load test.
<Load Test : KneeGuardKids3>