When is it required to use the Infant-thingy body support?

The Infant-thingy body support is required when:

• Using with children from 5–11 lb
• When the car seat headrest is used with a child who weighs less than 14 lb
• With a child who cannot sit upright unassisted

The body support is optional for children between 11–22 lb, provided the Infant-thingy head support is in use.