What type of sign is the "not suitable for children under three" symbol?

The "not suitable for children under three" symbol serves as an age restriction indicator because it specifically communicates that certain items or toys are not appropriate for children in that age group. This symbol helps caregivers and parents make informed decisions about the safety of products for young children, highlighting potential hazards that could arise from using them. This is particularly important in protecting the health and safety of children, as items that are not suitable may pose choking hazards or other risks. The clear visual indication of age restrictions thus plays a critical role in ensuring child safety, making it an essential feature for products aimed at young audiences.