The lap belt may ride up on your child's tummy, and the shoulder belt may rest on his neck, causing him to put the shoulder belt under his arm or back. Booster seats help safety belts fit properly. Read the booster seat's manual for specific instructions and weight limits. There are several types of booster seats.
Some boosters come with a removable shield.
Shield boosters are not approved for children weighing more than 40 pounds. Some boosters have high backs and removable harnesses. With the harness in place, the seat acts as a forward-facing child safety seat. Check the booster seat instructions for weight limitations when the seat is used with the harness. The high back is especially good if there are no head restraints for the child in the vehicle.